Add ServeDNS test for non-retryable EDE short-circuit and OPT stripping

* Use fwmark-aware route lookup for raw socket UDP checksum source

* Guard nil raw socket in sharedsock WriteTo

.github/DISCUSSION_TEMPLATE/ideas-feature-requests.yml

@@ -0,0 +1,130 @@
+body:
+  - type: markdown
+    attributes:
+      value: |
+        ## Ideas & Feature Requests
+
+        Use this category for feature requests, enhancements, integrations, and product ideas.
+
+        NetBird uses community traction in discussions — upvotes, replies, affected users, and use-case detail — as an input when deciding what should become a maintainer-curated issue or roadmap item. A clear problem statement is more useful than a solution-only request.
+
+        Please search first and add your use case to an existing discussion when one already exists.
+
+  - type: checkboxes
+    id: preflight
+    attributes:
+      label: Before posting
+      options:
+        - label: I searched existing discussions and issues for similar requests.
+          required: true
+        - label: I checked the documentation to confirm this is not already supported.
+          required: true
+        - label: This is a product idea or enhancement request, not a support question.
+          required: true
+        - label: I removed or anonymized sensitive details from examples and screenshots.
+          required: true
+
+  - type: dropdown
+    id: area
+    attributes:
+      label: Product area
+      description: Select every area this request touches.
+      multiple: true
+      options:
+        - Client / Agent
+        - CLI
+        - Desktop UI
+        - Mobile app
+        - Dashboard / Admin UI
+        - Management service / API
+        - Signal service
+        - Relay
+        - DNS
+        - Routes / Exit nodes
+        - NetBird SSH
+        - Access control policies
+        - Posture checks
+        - Identity provider / SSO
+        - Self-hosting / Deployment
+        - Kubernetes / Operator
+        - Terraform / Automation
+        - Documentation
+        - Other / not sure
+    validations:
+      required: true
+
+  - type: textarea
+    id: problem
+    attributes:
+      label: Problem or use case
+      description: What are you trying to accomplish, and what is difficult or impossible today?
+      placeholder: |
+        As a ...
+        I want to ...
+        Because ...
+    validations:
+      required: true
+
+  - type: textarea
+    id: proposal
+    attributes:
+      label: Proposed solution
+      description: Describe the behavior, workflow, API, UI, or integration you would like to see.
+    validations:
+      required: true
+
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives or workarounds considered
+      description: What have you tried today? Why is the current workaround not enough?
+
+  - type: textarea
+    id: impact
+    attributes:
+      label: Community impact and priority
+      description: Help us understand who benefits and how urgent this is.
+      placeholder: |
+        - Number of users/teams/peers affected:
+        - Deployment type: Cloud / self-hosted / both
+        - Frequency: daily / weekly / occasional
+        - Blocking production adoption? yes/no
+        - Related comments, discussions, or customer requests:
+    validations:
+      required: true
+
+  - type: textarea
+    id: examples
+    attributes:
+      label: Examples from other tools or products
+      description: If another tool solves this well, link or describe the behavior.
+
+  - type: textarea
+    id: security
+    attributes:
+      label: Security, privacy, and compatibility considerations
+      description: Note any access-control, audit, data retention, network, platform, or backward-compatibility concerns.
+
+  - type: textarea
+    id: implementation
+    attributes:
+      label: Implementation ideas
+      description: Optional. If you are familiar with the codebase or API, share possible implementation notes.
+
+  - type: dropdown
+    id: contribution
+    attributes:
+      label: Are you willing to help?
+      options:
+        - Yes, I can submit a PR if the approach is accepted.
+        - Yes, I can test or validate a proposed implementation.
+        - Yes, I can provide more use-case details.
+        - Not at this time.
+    validations:
+      required: true
+
+  - type: textarea
+    id: additional-context
+    attributes:
+      label: Additional context
+      description: Add screenshots, diagrams, links, or anything else that helps explain the request.

.github/DISCUSSION_TEMPLATE/issue-triage.yml

@@ -0,0 +1,237 @@
+body:
+  - type: markdown
+    attributes:
+      value: |
+        ## Issue Triage
+
+        Use this category for reproducible bugs and regressions in NetBird.
+
+        The more context you include, the faster we can validate and act on your report. If you're not sure whether something is a bug, **Q&A / Support** is a good starting point — we can always move the conversation here once we've confirmed it's a product issue.
+
+        Intermittent issues are useful too. Include the trigger, frequency, timing, and any logs or debug evidence you have, and we'll work from there.
+
+        Please don't include secrets, tokens, private keys, internal hostnames, or public IPs. Security vulnerabilities should be reported through the repository security policy rather than a public discussion.
+
+  - type: checkboxes
+    id: preflight
+    attributes:
+      label: Before posting
+      options:
+        - label: I searched existing discussions and issues, including closed ones, and checked the relevant docs.
+          required: true
+        - label: I believe this is a product bug rather than a configuration or setup question.
+          required: true
+        - label: I can reproduce this issue, or for intermittent issues I've included trigger, frequency, and timing details below.
+          required: true
+        - label: I removed or anonymized sensitive data from logs, screenshots, and configuration.
+          required: true
+
+  - type: dropdown
+    id: area
+    attributes:
+      label: Affected area
+      description: Select every area this report touches.
+      multiple: true
+      options:
+        - Client / Agent
+        - Reverse Proxy
+        - CLI
+        - Desktop UI
+        - Mobile app
+        - Peer connectivity
+        - DNS
+        - Routes / Exit nodes
+        - NetBird SSH
+        - Relay / Signal / NAT traversal
+        - Login / Authentication / IdP
+        - Dashboard / Admin UI
+        - Management service / API
+        - Access control policies / Posture checks
+        - Self-hosting / Deployment
+        - Kubernetes / Operator
+        - Documentation
+        - Other / not sure
+    validations:
+      required: true
+
+  - type: dropdown
+    id: deployment
+    attributes:
+      label: Deployment type
+      options:
+        - NetBird Cloud
+        - Self-hosted - quickstart script
+        - Self-hosted - advanced/custom deployment
+        - Local development build
+        - Not sure / environment I do not fully control
+    validations:
+      required: true
+
+  - type: dropdown
+    id: platform
+    attributes:
+      label: Operating system or environment
+      description: Select every environment involved in the reproduction.
+      multiple: true
+      options:
+        - Linux
+        - macOS
+        - Windows
+        - Android
+        - iOS
+        - FreeBSD
+        - OpenWRT
+        - Docker
+        - Kubernetes
+        - Synology
+        - Browser
+        - Other / not sure
+    validations:
+      required: true
+
+  - type: textarea
+    id: version
+    attributes:
+      label: NetBird version and upgrade status
+      description: Run `netbird version` where applicable. For self-hosted deployments, include management, signal, relay, and dashboard versions if available. If you cannot test on a current/supported version, explain why.
+      placeholder: |
+        Example:
+        - Client: 0.30.2
+        - Management: 0.30.2
+        - Signal: 0.30.2
+        - Relay: 0.30.2
+        - Dashboard: 0.30.2
+        - Upgrade status: reproduced on current version / cannot upgrade because ...
+    validations:
+      required: true
+
+  - type: dropdown
+    id: regression
+    attributes:
+      label: Did this work before?
+      options:
+        - Yes, this worked before
+        - No, this never worked
+        - Not sure
+    validations:
+      required: true
+
+  - type: textarea
+    id: regression-details
+    attributes:
+      label: Regression details
+      description: If this worked before, include the last known working version, first known broken version, and any recent upgrade, configuration, network, or IdP changes.
+      placeholder: |
+        - Last known working version:
+        - First known broken version:
+        - Recent changes:
+
+  - type: textarea
+    id: summary
+    attributes:
+      label: Summary
+      description: Briefly describe the reproducible bug.
+      placeholder: What is broken?
+    validations:
+      required: true
+
+  - type: textarea
+    id: current-behavior
+    attributes:
+      label: Current behavior
+      description: What happens now? Include exact errors, timeouts, UI messages, or failed commands when possible.
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected-behavior
+    attributes:
+      label: Expected behavior
+      description: What did you expect to happen instead?
+    validations:
+      required: true
+
+  - type: textarea
+    id: reproduction
+    attributes:
+      label: Steps to reproduce
+      description: Provide the smallest set of steps that reliably reproduces the bug. If the issue is intermittent, include the trigger, frequency, timing, and relevant timestamps.
+      placeholder: |
+        1. Configure ...
+        2. Run ...
+        3. Observe ...
+
+        For intermittent issues:
+        - Trigger:
+        - Frequency:
+        - Timing/timestamps:
+    validations:
+      required: true
+
+  - type: textarea
+    id: environment
+    attributes:
+      label: Environment and topology
+      description: Include the relevant topology and software involved in the reproduction. For UI/docs-only reports, write `N/A` if this does not apply. Use `None`, `Unknown`, or `N/A` where appropriate.
+      placeholder: |
+        - Peer A:
+        - Peer B:
+        - Same LAN or different networks:
+        - NAT/CGNAT/corporate firewall/mobile network:
+        - Other VPN software:
+        - Firewall, DNS, or endpoint security software:
+        - Routes, DNS, policies, posture checks, or SSH rules involved:
+        - IdP, reverse proxy, or browser involved:
+    validations:
+      required: true
+
+  - type: textarea
+    id: self-hosted-details
+    attributes:
+      label: Self-hosted details, if available
+      description: Optional. If you use self-hosting and have access to these details, include them. If you do not administer the environment, provide what you know and say what you cannot access.
+      placeholder: |
+        - Deployment method: quickstart / Docker Compose / Helm / operator / custom
+        - Management/signal/relay/dashboard versions:
+        - Reverse proxy:
+        - IdP/provider:
+        - STUN/TURN/coturn/relay details:
+        - Relevant component logs:
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs, status output, or debug evidence
+      description: |
+        For client, connectivity, DNS, route, relay/signal, or self-hosted reports, logs are essential — please include anonymized output from `netbird status -dA`, or a debug bundle via `netbird debug for 1m -AS -U`. Debug bundles are automatically deleted after 30 days.
+
+        For UI, dashboard, or documentation reports, leave the pre-filled `N/A`.
+      value: "N/A"
+      render: shell
+    validations:
+      required: true
+
+  - type: textarea
+    id: related-reports
+    attributes:
+      label: Related issues or discussions
+      description: Optional. Link similar reports you found while searching, if any.
+      placeholder: |
+        - Related issue/discussion:
+        - Why this may be the same or different:
+
+  - type: textarea
+    id: impact
+    attributes:
+      label: Impact
+      description: Optional. Help us understand priority. How many users, peers, environments, or workflows are affected? Is there a workaround?
+      placeholder: |
+        - Affected users/peers:
+        - Business or production impact:
+        - Workaround available:
+
+  - type: textarea
+    id: additional-context
+    attributes:
+      label: Additional context
+      description: Add links to related discussions, issues, docs, screenshots, recordings, or anything else that may help validation.

.github/DISCUSSION_TEMPLATE/q-a-support.yml

@@ -0,0 +1,146 @@
+body:
+  - type: markdown
+    attributes:
+      value: |
+        ## Q&A / Support
+
+        Use this category for questions about configuration, setup, self-hosted deployments, troubleshooting, and general NetBird usage.
+
+        This is community support and does not provide an SLA. For NetBird Cloud support, use the official support channel linked from the issue creation page. Please do not post secrets, tokens, private keys, internal hostnames, or public IPs unless you intentionally want them public.
+
+        If your question turns into a reproducible product defect, DevRel or a maintainer may ask you to open or move the conversation to Issue Triage.
+
+  - type: checkboxes
+    id: preflight
+    attributes:
+      label: Before posting
+      options:
+        - label: I searched existing discussions and issues for similar questions.
+          required: true
+        - label: I reviewed the relevant NetBird documentation or troubleshooting guide.
+          required: true
+        - label: I removed or anonymized sensitive data from logs, screenshots, and configuration.
+          required: true
+
+  - type: dropdown
+    id: topic
+    attributes:
+      label: Topic
+      multiple: true
+      options:
+        - Getting started
+        - Self-hosting
+        - Client / Agent
+        - CLI
+        - Desktop UI
+        - Mobile app
+        - Dashboard / Admin UI
+        - DNS
+        - Routes / Exit nodes
+        - NetBird SSH
+        - Relay
+        - Access control policies
+        - Posture checks
+        - Identity provider / SSO
+        - API
+        - Kubernetes / Operator
+        - Terraform / Automation
+        - Documentation
+        - Other / not sure
+    validations:
+      required: true
+
+  - type: dropdown
+    id: deployment
+    attributes:
+      label: Deployment type
+      options:
+        - NetBird Cloud
+        - Self-hosted - quickstart script
+        - Self-hosted - advanced/custom deployment
+        - Local development build
+        - Not sure
+    validations:
+      required: true
+
+  - type: dropdown
+    id: platform
+    attributes:
+      label: Operating system or environment
+      multiple: true
+      options:
+        - Linux
+        - macOS
+        - Windows
+        - Android
+        - iOS
+        - FreeBSD
+        - OpenWRT
+        - Docker
+        - Kubernetes
+        - Synology
+        - Browser
+        - Other / not sure
+    validations:
+      required: true
+
+  - type: input
+    id: version
+    attributes:
+      label: NetBird version
+      description: Run `netbird version` where applicable. For self-hosted deployments, include component versions if relevant.
+      placeholder: "Example: client 0.30.2, management 0.30.2"
+
+  - type: textarea
+    id: question
+    attributes:
+      label: Question
+      description: What are you trying to understand or accomplish?
+      placeholder: Describe your question clearly.
+    validations:
+      required: true
+
+  - type: textarea
+    id: goal
+    attributes:
+      label: Desired outcome
+      description: What would a successful answer help you do?
+      placeholder: |
+        I want to configure ...
+        I expected ...
+        I need help deciding ...
+
+  - type: textarea
+    id: attempted
+    attributes:
+      label: What have you tried?
+      description: Include commands, documentation links, configuration attempts, or troubleshooting steps already tried.
+      placeholder: |
+        - Read ...
+        - Ran ...
+        - Changed ...
+        - Observed ...
+
+  - type: textarea
+    id: environment
+    attributes:
+      label: Relevant environment details
+      description: Include redacted topology, IdP/provider, reverse proxy, firewall, DNS, route, policy, or self-hosted setup details that may affect the answer.
+      placeholder: |
+        - Deployment:
+        - Components involved:
+        - Network/topology:
+        - Related config:
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs or output
+      description: Optional. Include anonymized logs, command output, screenshots, or `netbird status -dA` if relevant.
+      render: shell
+
+  - type: textarea
+    id: additional-context
+    attributes:
+      label: Additional context
+      description: Add links, diagrams, screenshots, or other details that may help the community answer.

.github/ISSUE_TEMPLATE/bug-issue-report.md

@@ -1,71 +0,0 @@
----
-name: Bug/Issue report
-about: Create a report to help us improve
-title: ''
-labels: ['triage-needed']
-assignees: ''
-
----
-
-**Describe the problem**
-
-A clear and concise description of what the problem is.
-
-**To Reproduce**
-
-Steps to reproduce the behavior:
-1. Go to '...'
-2. Click on '....'
-3. Scroll down to '....'
-4. See error
-
-**Expected behavior**
-
-A clear and concise description of what you expected to happen.
-
-**Are you using NetBird Cloud?**
-
-Please specify whether you use NetBird Cloud or self-host NetBird's control plane.
-
-**NetBird version**
-
-`netbird version`
-
-**Is any other VPN software installed?**
-
-If yes, which one?
-
-**Debug output**
-
-To help us resolve the problem, please attach the following anonymized status output
-
-  netbird status -dA
-
-Create and upload a debug bundle, and share the returned file key:
-
-  netbird debug for 1m -AS -U
-
-*Uploaded files are automatically deleted after 30 days.*
-
-
-Alternatively, create the file only and attach it here manually:
-
-  netbird debug for 1m -AS
-
-
-**Screenshots**
-
-If applicable, add screenshots to help explain your problem.
-
-**Additional context**
-
-Add any other context about the problem here.
-
-**Have you tried these troubleshooting steps?**
-- [ ] Reviewed [client troubleshooting](https://docs.netbird.io/how-to/troubleshooting-client) (if applicable)
-- [ ] Checked for newer NetBird versions
-- [ ] Searched for similar issues on GitHub (including closed ones)
-- [ ] Restarted the NetBird client
-- [ ] Disabled other VPN software
-- [ ] Checked firewall settings
-

.github/ISSUE_TEMPLATE/config.yml

@@ -1,14 +1,26 @@
-blank_issues_enabled: true
+blank_issues_enabled: false
 contact_links:
-  - name: Community Support
+  - name: Start an Issue Triage discussion
+    url: https://github.com/netbirdio/netbird/discussions/new?category=issue-triage
+    about: Report a bug, regression, or unexpected behavior so DevRel can validate it before it becomes an issue.
+  - name: Propose an idea or feature request
+    url: https://github.com/netbirdio/netbird/discussions/new?category=ideas-feature-requests
+    about: Share feature requests, enhancements, and integration ideas for community feedback and prioritization.
+  - name: Ask a Q&A / Support question
+    url: https://github.com/netbirdio/netbird/discussions/new?category=q-a-support
+    about: Get help with setup, configuration, self-hosting, troubleshooting, and general usage.
+  - name: Security vulnerability disclosure
+    url: https://github.com/netbirdio/netbird/security/policy
+    about: Please do not report security vulnerabilities in public issues or discussions.
+  - name: Community Support Forum
     url: https://forum.netbird.io/
-    about: Community support forum
+    about: Community support forum.
   - name: Cloud Support
     url: https://docs.netbird.io/help/report-bug-issues
-    about: Contact us for support
-  - name: Client/Connection Troubleshooting
+    about: Contact NetBird for Cloud support.
+  - name: Client / Connection Troubleshooting
     url: https://docs.netbird.io/help/troubleshooting-client
-    about: See our client troubleshooting guide for help addressing common issues
+    about: See the client troubleshooting guide for common connectivity issues.
   - name: Self-host Troubleshooting
     url: https://docs.netbird.io/selfhosted/troubleshooting
-    about: See our self-host troubleshooting guide for help addressing common issues
+    about: See the self-host troubleshooting guide for common deployment issues.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,20 +0,0 @@
----
-name: Feature request
-about: Suggest an idea for this project
-title: ''
-labels: ['feature-request']
-assignees: ''
-
----
-
-**Is your feature request related to a problem? Please describe.**
-A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
-
-**Describe the solution you'd like**
-A clear and concise description of what you want to happen.
-
-**Describe alternatives you've considered**
-A clear and concise description of any alternative solutions or features you've considered.
-
-**Additional context**
-Add any other context or screenshots about the feature request here.

.github/ISSUE_TEMPLATE/validated_issue.yml

@@ -0,0 +1,128 @@
+name: Validated issue
+description: Maintainer/DevRel only. Create an issue after a discussion has been validated or for internally validated work.
+title: "[Validated]: "
+body:
+  - type: markdown
+    attributes:
+      value: |
+        ## Discussion-first issue policy
+
+        Issues are maintainer-curated work items. Community reports and feature requests should start in [Discussions](https://github.com/netbirdio/netbird/discussions) so DevRel can validate, reproduce, and route them before engineering time is committed.
+
+        Use this form when:
+        - A discussion has been validated and should become actionable work.
+        - A maintainer is opening internally validated work that can bypass the discussion-first flow.
+
+        Issues opened without a relevant validated discussion or maintainer context may be closed and redirected to Discussions.
+
+  - type: checkboxes
+    id: validation-checks
+    attributes:
+      label: Validation checklist
+      options:
+        - label: This issue is linked to a validated discussion, or it is being opened directly by a maintainer.
+          required: true
+        - label: The report has enough context for engineering to act on it without re-triaging from scratch.
+          required: true
+        - label: Sensitive data, secrets, private keys, internal hostnames, and public IPs have been removed or intentionally disclosed.
+          required: true
+
+  - type: dropdown
+    id: issue-type
+    attributes:
+      label: Issue type
+      options:
+        - Bug / Regression
+        - Feature / Enhancement
+        - Documentation
+        - Maintenance / Refactor
+        - Cross-repository coordination
+        - Other
+    validations:
+      required: true
+
+  - type: input
+    id: source-discussion
+    attributes:
+      label: Source discussion
+      description: Link the GitHub Discussion that was validated. Maintainers bypassing the flow can write "Maintainer-created" and explain why below.
+      placeholder: https://github.com/netbirdio/netbird/discussions/1234
+    validations:
+      required: true
+
+  - type: input
+    id: validation-owner
+    attributes:
+      label: Validation owner
+      description: GitHub handle of the DevRel team member or maintainer who validated this work.
+      placeholder: "@username"
+    validations:
+      required: true
+
+  - type: dropdown
+    id: target-repository
+    attributes:
+      label: Target repository
+      description: Where should the implementation work happen?
+      options:
+        - netbirdio/netbird
+        - netbirdio/dashboard
+        - netbirdio/kubernetes-operator
+        - netbirdio/docs
+        - Multiple repositories
+        - Unknown / needs routing
+    validations:
+      required: true
+
+  - type: textarea
+    id: summary
+    attributes:
+      label: Summary
+      description: Concise description of the validated work.
+      placeholder: What needs to be fixed, changed, documented, or built?
+    validations:
+      required: true
+
+  - type: textarea
+    id: evidence
+    attributes:
+      label: Validation evidence
+      description: For bugs, include reproduction status, affected versions, logs, and environment. For features, include community traction, affected users, and alignment notes.
+      placeholder: |
+        - Reproduced by:
+        - Affected versions / platforms:
+        - Community signal:
+        - Related logs or screenshots:
+    validations:
+      required: true
+
+  - type: textarea
+    id: scope
+    attributes:
+      label: Proposed scope
+      description: Describe what is in scope and, if helpful, what is explicitly out of scope.
+      placeholder: |
+        In scope:
+        - ...
+
+        Out of scope:
+        - ...
+    validations:
+      required: true
+
+  - type: textarea
+    id: acceptance-criteria
+    attributes:
+      label: Acceptance criteria
+      description: What must be true for this issue to be closed?
+      placeholder: |
+        - [ ] ...
+        - [ ] ...
+    validations:
+      required: true
+
+  - type: textarea
+    id: additional-context
+    attributes:
+      label: Additional context
+      description: Links to related PRs, docs, issues in other repositories, roadmap items, or implementation notes.

.github/workflows/golangci-lint.yml

@@ -19,7 +19,7 @@ jobs:
       - name: codespell
         uses: codespell-project/actions-codespell@v2
         with:
-          ignore_words_list: erro,clienta,hastable,iif,groupd,testin,groupe,cros,ans,deriver,te,userA
+          ignore_words_list: erro,clienta,hastable,iif,groupd,testin,groupe,cros,ans,deriver,te,userA,ede,additionals
           skip: go.mod,go.sum,**/proxy/web/**
   golangci:
     strategy:

.github/workflows/proto-version-check.yml

@@ -0,0 +1,62 @@
+name: Proto Version Check
+
+on:
+  pull_request:
+    paths:
+      - "**/*.pb.go"
+
+jobs:
+  check-proto-versions:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check for proto tool version changes
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const files = await github.paginate(github.rest.pulls.listFiles, {
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: context.issue.number,
+              per_page: 100,
+            });
+
+            const pbFiles = files.filter(f => f.filename.endsWith('.pb.go'));
+            const missingPatch = pbFiles.filter(f => !f.patch).map(f => f.filename);
+            if (missingPatch.length > 0) {
+              core.setFailed(
+                `Cannot inspect patch data for:\n` +
+                missingPatch.map(f => `- ${f}`).join('\n') +
+                `\nThis can happen with very large PRs. Verify proto versions manually.`
+              );
+              return;
+            }
+            const versionPattern = /^[+-]\s*\/\/\s+protoc(?:-gen-go)?\s+v[\d.]+/;
+            const violations = [];
+
+            for (const file of pbFiles) {
+              const changed = file.patch
+                .split('\n')
+                .filter(line => versionPattern.test(line));
+              if (changed.length > 0) {
+                violations.push({
+                  file: file.filename,
+                  lines: changed,
+                });
+              }
+            }
+
+            if (violations.length > 0) {
+              const details = violations.map(v =>
+                `${v.file}:\n${v.lines.map(l => '  ' + l).join('\n')}`
+              ).join('\n\n');
+
+              core.setFailed(
+                `Proto version strings changed in generated files.\n` +
+                `This usually means the wrong protoc or protoc-gen-go version was used.\n` +
+                `Regenerate with the matching tool versions.\n\n` +
+                details
+              );
+              return;
+            }
+
+            console.log('No proto version string changes detected');

.github/workflows/release.yml

@@ -9,7 +9,7 @@ on:
   pull_request:
 
 env:
-  SIGN_PIPE_VER: "v0.1.1"
+  SIGN_PIPE_VER: "v0.1.4"
   GORELEASER_VER: "v2.14.3"
   PRODUCT_NAME: "NetBird"
   COPYRIGHT: "NetBird GmbH"
@@ -114,7 +114,13 @@ jobs:
           retention-days: 30
 
   release:
-    runs-on: ubuntu-latest-m
+    runs-on: ubuntu-24.04-8-core
+    outputs:
+      release_artifact_url: ${{ steps.upload_release.outputs.artifact-url }}
+      linux_packages_artifact_url: ${{ steps.upload_linux_packages.outputs.artifact-url }}
+      windows_packages_artifact_url: ${{ steps.upload_windows_packages.outputs.artifact-url }}
+      macos_packages_artifact_url: ${{ steps.upload_macos_packages.outputs.artifact-url }}
+      ghcr_images: ${{ steps.tag_and_push_images.outputs.images_markdown }}
     env:
       flags: ""
     steps:
@@ -213,10 +219,13 @@ jobs:
         if: always()
         run: rm -f /tmp/gpg-rpm-signing-key.asc
       - name: Tag and push images (amd64 only)
+        id: tag_and_push_images
         if: |
           (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository) ||
           (github.event_name == 'push' && github.ref == 'refs/heads/main')
         run: |
+          set -euo pipefail
+
           resolve_tags() {
             if [[ "${{ github.event_name }}" == "pull_request" ]]; then
               echo "pr-${{ github.event.pull_request.number }}"
@@ -225,6 +234,17 @@ jobs:
             fi
           }
 
+          ghcr_package_url() {
+            local image="$1" package encoded_package
+            package="${image#ghcr.io/}"
+            package="${package#*/}"
+            package="${package%%:*}"
+            encoded_package="${package//\//%2F}"
+            echo "https://github.com/orgs/netbirdio/packages/container/package/${encoded_package}"
+          }
+
+          image_refs=()
+
           tag_and_push() {
             local src="$1" img_name tag dst
             img_name="${src%%:*}"
@@ -233,35 +253,56 @@ jobs:
               echo "Tagging ${src} -> ${dst}"
               docker tag "$src" "$dst"
               docker push "$dst"
+              image_refs+=("$dst")
             done
           }
 
-          export -f tag_and_push resolve_tags
+          cat > /tmp/goreleaser-artifacts.json <<'JSON'
+          ${{ steps.goreleaser.outputs.artifacts }}
+          JSON
 
-          echo '${{ steps.goreleaser.outputs.artifacts }}' | \
-            jq -r '.[] | select(.type == "Docker Image") | select(.goarch == "amd64") | .name' | \
-            grep '^ghcr.io/' | while read -r SRC; do
-              tag_and_push "$SRC"
-            done
+          mapfile -t src_images < <(
+            jq -r '.[] | select(.type == "Docker Image") | select(.goarch == "amd64") | .name | select(startswith("ghcr.io/"))' /tmp/goreleaser-artifacts.json
+          )
+
+          for src in "${src_images[@]}"; do
+            tag_and_push "$src"
+          done
+
+          {
+            echo "images_markdown<<EOF"
+            if [[ ${#image_refs[@]} -eq 0 ]]; then
+              echo "_No GHCR images were pushed._"
+            else
+              printf '%s\n' "${image_refs[@]}" | sort -u | while read -r image; do
+                printf -- '- [`%s`](%s)\n' "$image" "$(ghcr_package_url "$image")"
+              done
+            fi
+            echo "EOF"
+          } >> "$GITHUB_OUTPUT"
       - name: upload non tags for debug purposes
+        id: upload_release
         uses: actions/upload-artifact@v4
         with:
           name: release
           path: dist/
           retention-days: 7
       - name: upload linux packages
+        id: upload_linux_packages
         uses: actions/upload-artifact@v4
         with:
           name: linux-packages
           path: dist/netbird_linux**
           retention-days: 7
       - name: upload windows packages
+        id: upload_windows_packages
         uses: actions/upload-artifact@v4
         with:
           name: windows-packages
           path: dist/netbird_windows**
           retention-days: 7
       - name: upload macos packages
+        id: upload_macos_packages
         uses: actions/upload-artifact@v4
         with:
           name: macos-packages
@@ -270,6 +311,8 @@ jobs:
 
   release_ui:
     runs-on: ubuntu-latest
+    outputs:
+      release_ui_artifact_url: ${{ steps.upload_release_ui.outputs.artifact-url }}
     steps:
       - name: Parse semver string
         id: semver_parser
@@ -360,6 +403,7 @@ jobs:
         if: always()
         run: rm -f /tmp/gpg-rpm-signing-key.asc
       - name: upload non tags for debug purposes
+        id: upload_release_ui
         uses: actions/upload-artifact@v4
         with:
           name: release-ui
@@ -368,6 +412,8 @@ jobs:
 
   release_ui_darwin:
     runs-on: macos-latest
+    outputs:
+      release_ui_darwin_artifact_url: ${{ steps.upload_release_ui_darwin.outputs.artifact-url }}
     steps:
       - if: ${{ !startsWith(github.ref, 'refs/tags/v') }}
         run: echo "flags=--snapshot" >> $GITHUB_ENV
@@ -402,15 +448,258 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       - name: upload non tags for debug purposes
+        id: upload_release_ui_darwin
         uses: actions/upload-artifact@v4
         with:
           name: release-ui-darwin
           path: dist/
           retention-days: 3
 
-  trigger_signer:
+  test_windows_installer:
+    name: "Windows Installer / Build Test"
+    runs-on: windows-2022
+    needs: [release, release_ui]
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arch: amd64
+            wintun_arch: amd64
+          - arch: arm64
+            wintun_arch: arm64
+    defaults:
+      run:
+        shell: powershell
+    env:
+      PackageWorkdir: netbird_windows_${{ matrix.arch }}
+      downloadPath: '${{ github.workspace }}\temp'
+    steps:
+      - name: Parse semver string
+        id: semver_parser
+        uses: booxmedialtd/ws-action-parse-semver@v1
+        with:
+          input_string: ${{ (startsWith(github.ref, 'refs/tags/v') && github.ref) || 'refs/tags/v0.0.0' }}
+          version_extractor_regex: '\/v(.*)$'
+
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Add 7-Zip to PATH
+        run: echo "C:\Program Files\7-Zip" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+
+      - name: Download release artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: release
+          path: release
+
+      - name: Download UI release artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: release-ui
+          path: release-ui
+
+      - name: Stage binaries into dist
+        run: |
+          $workdir = "dist\${{ env.PackageWorkdir }}"
+          New-Item -ItemType Directory -Force -Path $workdir | Out-Null
+          $client = Get-ChildItem -Recurse -Path release -Filter "netbird_*_windows_${{ matrix.arch }}.tar.gz" | Select-Object -First 1
+          $ui = Get-ChildItem -Recurse -Path release-ui -Filter "netbird-ui-windows_*_windows_${{ matrix.arch }}.tar.gz" | Select-Object -First 1
+          if (-not $client) { Write-Host "::error::client tarball not found for ${{ matrix.arch }}"; exit 1 }
+          if (-not $ui) { Write-Host "::error::ui tarball not found for ${{ matrix.arch }}"; exit 1 }
+          Write-Host "Client: $($client.FullName)"
+          Write-Host "UI:     $($ui.FullName)"
+          tar -zvxf $client.FullName -C $workdir
+          tar -zvxf $ui.FullName -C $workdir
+          Get-ChildItem $workdir
+
+      - name: Download wintun
+        uses: carlosperate/download-file-action@v2
+        id: download-wintun
+        with:
+          file-url: https://pkgs.netbird.io/wintun/wintun-0.14.1.zip
+          file-name: wintun.zip
+          location: ${{ env.downloadPath }}
+          sha256: '07c256185d6ee3652e09fa55c0b673e2624b565e02c4b9091c79ca7d2f24ef51'
+
+      - name: Decompress wintun files
+        run: tar -zvxf "${{ steps.download-wintun.outputs.file-path }}" -C ${{ env.downloadPath }}
+
+      - name: Move wintun.dll into dist
+        run: mv ${{ env.downloadPath }}\wintun\bin\${{ matrix.wintun_arch }}\wintun.dll ${{ github.workspace }}\dist\${{ env.PackageWorkdir }}\
+
+      - name: Download Mesa3D (amd64 only)
+        uses: carlosperate/download-file-action@v2
+        id: download-mesa3d
+        if: matrix.arch == 'amd64'
+        with:
+          file-url: https://downloads.fdossena.com/Projects/Mesa3D/Builds/MesaForWindows-x64-20.1.8.7z
+          file-name: mesa3d.7z
+          location: ${{ env.downloadPath }}
+          sha256: '71c7cb64ec229a1d6b8d62fa08e1889ed2bd17c0eeede8689daf0f25cb31d6b9'
+
+      - name: Extract Mesa3D driver (amd64 only)
+        if: matrix.arch == 'amd64'
+        run: 7z x -o"${{ env.downloadPath }}" "${{ env.downloadPath }}/mesa3d.7z"
+
+      - name: Move opengl32.dll into dist (amd64 only)
+        if: matrix.arch == 'amd64'
+        run: mv ${{ env.downloadPath }}\opengl32.dll ${{ github.workspace }}\dist\${{ env.PackageWorkdir }}\
+
+      - name: Download EnVar plugin for NSIS
+        uses: carlosperate/download-file-action@v2
+        with:
+          file-url: https://nsis.sourceforge.io/mediawiki/images/7/7f/EnVar_plugin.zip
+          file-name: envar_plugin.zip
+          location: ${{ github.workspace }}
+
+      - name: Extract EnVar plugin
+        run: 7z x -o"${{ github.workspace }}/NSIS_Plugins" "${{ github.workspace }}/envar_plugin.zip"
+
+      - name: Download ShellExecAsUser plugin for NSIS (amd64 only)
+        uses: carlosperate/download-file-action@v2
+        if: matrix.arch == 'amd64'
+        with:
+          file-url: https://nsis.sourceforge.io/mediawiki/images/6/68/ShellExecAsUser_amd64-Unicode.7z
+          file-name: ShellExecAsUser_amd64-Unicode.7z
+          location: ${{ github.workspace }}
+
+      - name: Extract ShellExecAsUser plugin (amd64 only)
+        if: matrix.arch == 'amd64'
+        run: 7z x -o"${{ github.workspace }}/NSIS_Plugins" "${{ github.workspace }}/ShellExecAsUser_amd64-Unicode.7z"
+
+      - name: Build NSIS installer
+        uses: joncloud/makensis-action@v3.3
+        with:
+          additional-plugin-paths: ${{ github.workspace }}/NSIS_Plugins/Plugins
+          script-file: client/installer.nsis
+          arguments: "/V4 /DARCH=${{ matrix.arch }}"
+        env:
+          APPVER: ${{ steps.semver_parser.outputs.major }}.${{ steps.semver_parser.outputs.minor }}.${{ steps.semver_parser.outputs.patch }}.${{ github.run_id }}
+
+      - name: Rename NSIS installer
+        run: mv netbird-installer.exe netbird_installer_test_windows_${{ matrix.arch }}.exe
+
+      - name: Install WiX
+        run: |
+          dotnet tool install --global wix --version 6.0.2
+          wix extension add WixToolset.Util.wixext/6.0.2
+
+      - name: Build MSI installer
+        env:
+          NETBIRD_VERSION: "${{ steps.semver_parser.outputs.fullversion }}"
+        run: wix build -arch ${{ matrix.arch == 'amd64' && 'x64' || 'arm64' }} -ext WixToolset.Util.wixext -o netbird_installer_test_windows_${{ matrix.arch }}.msi .\client\netbird.wxs -d ProcessorArchitecture=${{ matrix.arch == 'amd64' && 'x64' || 'arm64' }} -d ArchSuffix=${{ matrix.arch }}
+
+      - name: Upload installer artifacts
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: windows-installer-test-${{ matrix.arch }}
+          path: |
+            netbird_installer_test_windows_${{ matrix.arch }}.exe
+            netbird_installer_test_windows_${{ matrix.arch }}.msi
+          retention-days: 3
+
+  comment_release_artifacts:
+    name: Comment release artifacts
     runs-on: ubuntu-latest
     needs: [release, release_ui, release_ui_darwin]
+    if: ${{ always() && github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository }}
+    permissions:
+      contents: read
+      issues: write
+      pull-requests: write
+    steps:
+      - name: Create or update PR comment
+        uses: actions/github-script@v7
+        env:
+          RELEASE_RESULT: ${{ needs.release.result }}
+          RELEASE_UI_RESULT: ${{ needs.release_ui.result }}
+          RELEASE_UI_DARWIN_RESULT: ${{ needs.release_ui_darwin.result }}
+          RELEASE_ARTIFACT_URL: ${{ needs.release.outputs.release_artifact_url }}
+          LINUX_PACKAGES_ARTIFACT_URL: ${{ needs.release.outputs.linux_packages_artifact_url }}
+          WINDOWS_PACKAGES_ARTIFACT_URL: ${{ needs.release.outputs.windows_packages_artifact_url }}
+          MACOS_PACKAGES_ARTIFACT_URL: ${{ needs.release.outputs.macos_packages_artifact_url }}
+          RELEASE_UI_ARTIFACT_URL: ${{ needs.release_ui.outputs.release_ui_artifact_url }}
+          RELEASE_UI_DARWIN_ARTIFACT_URL: ${{ needs.release_ui_darwin.outputs.release_ui_darwin_artifact_url }}
+          GHCR_IMAGES_MARKDOWN: ${{ needs.release.outputs.ghcr_images }}
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const marker = '<!-- netbird-release-artifacts -->';
+            const { owner, repo } = context.repo;
+            const issue_number = context.payload.pull_request.number;
+            const runUrl = `${context.serverUrl}/${owner}/${repo}/actions/runs/${context.runId}`;
+            const shortSha = context.payload.pull_request.head.sha.slice(0, 7);
+
+            const artifactCell = (url, result) => {
+              if (url) return `[Download](${url})`;
+              return result && result !== 'success' ? `_Not available (${result})_` : '_Not available_';
+            };
+
+            const artifacts = [
+              ['All release artifacts', process.env.RELEASE_ARTIFACT_URL, process.env.RELEASE_RESULT],
+              ['Linux packages', process.env.LINUX_PACKAGES_ARTIFACT_URL, process.env.RELEASE_RESULT],
+              ['Windows packages', process.env.WINDOWS_PACKAGES_ARTIFACT_URL, process.env.RELEASE_RESULT],
+              ['macOS packages', process.env.MACOS_PACKAGES_ARTIFACT_URL, process.env.RELEASE_RESULT],
+              ['UI artifacts', process.env.RELEASE_UI_ARTIFACT_URL, process.env.RELEASE_UI_RESULT],
+              ['UI macOS artifacts', process.env.RELEASE_UI_DARWIN_ARTIFACT_URL, process.env.RELEASE_UI_DARWIN_RESULT],
+            ];
+
+            const artifactRows = artifacts
+              .map(([name, url, result]) => `| ${name} | ${artifactCell(url, result)} |`)
+              .join('\n');
+
+            const ghcrImages = (process.env.GHCR_IMAGES_MARKDOWN || '').trim() || '_No GHCR images were pushed._';
+
+            const body = [
+              marker,
+              '## Release artifacts',
+              '',
+              `Built for PR head \`${shortSha}\` in [workflow run #${process.env.GITHUB_RUN_NUMBER}](${runUrl}).`,
+              '',
+              '| Artifact | Link |',
+              '| --- | --- |',
+              artifactRows,
+              '',
+              '### GHCR images (amd64)',
+              ghcrImages,
+              '',
+              '_This comment is updated by the Release workflow. Artifact links expire according to the workflow retention policy._',
+            ].join('\n');
+
+            const comments = await github.paginate(github.rest.issues.listComments, {
+              owner,
+              repo,
+              issue_number,
+              per_page: 100,
+            });
+
+            const previous = comments.find(comment =>
+              comment.user?.type === 'Bot' && comment.body?.includes(marker)
+            );
+
+            if (previous) {
+              await github.rest.issues.updateComment({
+                owner,
+                repo,
+                comment_id: previous.id,
+                body,
+              });
+              core.info(`Updated release artifacts comment ${previous.id}`);
+            } else {
+              const { data } = await github.rest.issues.createComment({
+                owner,
+                repo,
+                issue_number,
+                body,
+              });
+              core.info(`Created release artifacts comment ${data.id}`);
+            }
+
+  trigger_signer:
+    runs-on: ubuntu-latest
+    needs: [release, release_ui, release_ui_darwin, test_windows_installer]
     if: startsWith(github.ref, 'refs/tags/')
     steps:
       - name: Trigger binaries sign pipelines

.github/workflows/sync-tag.yml

@@ -9,6 +9,8 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}-${{ github.head_ref || github.actor_id }}
   cancel-in-progress: true
 
+# Receiving workflows (cloud sync-tag, mobile bump-netbird) expect the short
+# tag form (e.g. v0.30.0), not refs/tags/v0.30.0 — github.ref_name, not github.ref.
 jobs:
   trigger_sync_tag:
     runs-on: ubuntu-latest
@@ -20,4 +22,30 @@ jobs:
           ref: main
           repo: ${{ secrets.UPSTREAM_REPO }}
           token: ${{ secrets.NC_GITHUB_TOKEN }}
+          inputs: '{ "tag": "${{ github.ref_name }}" }'
+
+  trigger_android_bump:
+    runs-on: ubuntu-latest
+    if: github.event.created && !github.event.deleted && startsWith(github.ref, 'refs/tags/v') && !contains(github.ref_name, '-')
+    steps:
+      - name: Trigger android-client submodule bump
+        uses: benc-uk/workflow-dispatch@7a027648b88c2413826b6ddd6c76114894dc5ec4 # v1.3.1
+        with:
+          workflow: bump-netbird.yml
+          ref: main
+          repo: netbirdio/android-client
+          token: ${{ secrets.NC_GITHUB_TOKEN }}
+          inputs: '{ "tag": "${{ github.ref_name }}" }'
+
+  trigger_ios_bump:
+    runs-on: ubuntu-latest
+    if: github.event.created && !github.event.deleted && startsWith(github.ref, 'refs/tags/v') && !contains(github.ref_name, '-')
+    steps:
+      - name: Trigger ios-client submodule bump
+        uses: benc-uk/workflow-dispatch@7a027648b88c2413826b6ddd6c76114894dc5ec4 # v1.3.1
+        with:
+          workflow: bump-netbird.yml
+          ref: main
+          repo: netbirdio/ios-client
+          token: ${{ secrets.NC_GITHUB_TOKEN }}
           inputs: '{ "tag": "${{ github.ref_name }}" }'

.golangci.yaml

@@ -58,6 +58,11 @@ linters:
     govet:
       enable:
         - nilness
+      disable:
+        # The inline analyzer flags x/exp/maps Clone/Clear with //go:fix inline
+        # directives but cannot perform the rewrite due to generic type
+        # parameter inference limitations in the Go inliner.
+        - inline
       enable-all: false
     revive:
       rules:

Makefile

@@ -5,7 +5,7 @@ GOLANGCI_LINT := $(shell pwd)/bin/golangci-lint
 $(GOLANGCI_LINT):
 	@echo "Installing golangci-lint..."
 	@mkdir -p ./bin
-	@GOBIN=$(shell pwd)/bin go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
+	@GOBIN=$(shell pwd)/bin go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@latest
 
 # Lint only changed files (fast, for pre-push)
 lint: $(GOLANGCI_LINT)

client/Dockerfile

@@ -17,6 +17,7 @@ ENV \
     NETBIRD_BIN="/usr/local/bin/netbird" \
     NB_LOG_FILE="console,/var/log/netbird/client.log" \
     NB_DAEMON_ADDR="unix:///var/run/netbird.sock" \
+    NB_ENABLE_CAPTURE="false" \
     NB_ENTRYPOINT_SERVICE_TIMEOUT="30"
 
 ENTRYPOINT [ "/usr/local/bin/netbird-entrypoint.sh" ]

client/Dockerfile-rootless

@@ -23,6 +23,7 @@ ENV \
     NB_DAEMON_ADDR="unix:///var/lib/netbird/netbird.sock" \
     NB_LOG_FILE="console,/var/lib/netbird/client.log" \
     NB_DISABLE_DNS="true" \
+    NB_ENABLE_CAPTURE="false" \
     NB_ENTRYPOINT_SERVICE_TIMEOUT="30"
 
 ENTRYPOINT [ "/usr/local/bin/netbird-entrypoint.sh" ]

client/android/client.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"slices"
 	"sync"
+	"time"
 
 	"golang.org/x/exp/maps"
 
@@ -15,6 +16,7 @@ import (
 
 	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/internal"
+	"github.com/netbirdio/netbird/client/internal/debug"
 	"github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/listener"
 	"github.com/netbirdio/netbird/client/internal/peer"
@@ -26,6 +28,7 @@ import (
 	"github.com/netbirdio/netbird/formatter"
 	"github.com/netbirdio/netbird/route"
 	"github.com/netbirdio/netbird/shared/management/domain"
+	types "github.com/netbirdio/netbird/upload-server/types"
 )
 
 // ConnectionListener export internal Listener for mobile
@@ -68,7 +71,30 @@ type Client struct {
 	uiVersion             string
 	networkChangeListener listener.NetworkChangeListener
 
+	stateMu       sync.RWMutex
 	connectClient *internal.ConnectClient
+	config        *profilemanager.Config
+	cacheDir      string
+}
+
+func (c *Client) setState(cfg *profilemanager.Config, cacheDir string, cc *internal.ConnectClient) {
+	c.stateMu.Lock()
+	defer c.stateMu.Unlock()
+	c.config = cfg
+	c.cacheDir = cacheDir
+	c.connectClient = cc
+}
+
+func (c *Client) stateSnapshot() (*profilemanager.Config, string, *internal.ConnectClient) {
+	c.stateMu.RLock()
+	defer c.stateMu.RUnlock()
+	return c.config, c.cacheDir, c.connectClient
+}
+
+func (c *Client) getConnectClient() *internal.ConnectClient {
+	c.stateMu.RLock()
+	defer c.stateMu.RUnlock()
+	return c.connectClient
 }
 
 // NewClient instantiate a new Client
@@ -93,6 +119,7 @@ func (c *Client) Run(platformFiles PlatformFiles, urlOpener URLOpener, isAndroid
 
 	cfgFile := platformFiles.ConfigurationFilePath()
 	stateFile := platformFiles.StateFilePath()
+	cacheDir := platformFiles.CacheDir()
 
 	log.Infof("Starting client with config: %s, state: %s", cfgFile, stateFile)
 
@@ -124,8 +151,9 @@ func (c *Client) Run(platformFiles PlatformFiles, urlOpener URLOpener, isAndroid
 
 	// todo do not throw error in case of cancelled context
 	ctx = internal.CtxInitState(ctx)
-	c.connectClient = internal.NewConnectClient(ctx, cfg, c.recorder)
-	return c.connectClient.RunOnAndroid(c.tunAdapter, c.iFaceDiscover, c.networkChangeListener, slices.Clone(dns.items), dnsReadyListener, stateFile)
+	connectClient := internal.NewConnectClient(ctx, cfg, c.recorder)
+	c.setState(cfg, cacheDir, connectClient)
+	return connectClient.RunOnAndroid(c.tunAdapter, c.iFaceDiscover, c.networkChangeListener, slices.Clone(dns.items), dnsReadyListener, stateFile, cacheDir)
 }
 
 // RunWithoutLogin we apply this type of run function when the backed has been started without UI (i.e. after reboot).
@@ -135,6 +163,7 @@ func (c *Client) RunWithoutLogin(platformFiles PlatformFiles, dns *DNSList, dnsR
 
 	cfgFile := platformFiles.ConfigurationFilePath()
 	stateFile := platformFiles.StateFilePath()
+	cacheDir := platformFiles.CacheDir()
 
 	log.Infof("Starting client without login with config: %s, state: %s", cfgFile, stateFile)
 
@@ -157,8 +186,9 @@ func (c *Client) RunWithoutLogin(platformFiles PlatformFiles, dns *DNSList, dnsR
 
 	// todo do not throw error in case of cancelled context
 	ctx = internal.CtxInitState(ctx)
-	c.connectClient = internal.NewConnectClient(ctx, cfg, c.recorder)
-	return c.connectClient.RunOnAndroid(c.tunAdapter, c.iFaceDiscover, c.networkChangeListener, slices.Clone(dns.items), dnsReadyListener, stateFile)
+	connectClient := internal.NewConnectClient(ctx, cfg, c.recorder)
+	c.setState(cfg, cacheDir, connectClient)
+	return connectClient.RunOnAndroid(c.tunAdapter, c.iFaceDiscover, c.networkChangeListener, slices.Clone(dns.items), dnsReadyListener, stateFile, cacheDir)
 }
 
 // Stop the internal client and free the resources
@@ -173,11 +203,12 @@ func (c *Client) Stop() {
 }
 
 func (c *Client) RenewTun(fd int) error {
-	if c.connectClient == nil {
+	cc := c.getConnectClient()
+	if cc == nil {
 		return fmt.Errorf("engine not running")
 	}
 
-	e := c.connectClient.Engine()
+	e := cc.Engine()
 	if e == nil {
 		return fmt.Errorf("engine not initialized")
 	}
@@ -185,6 +216,73 @@ func (c *Client) RenewTun(fd int) error {
 	return e.RenewTun(fd)
 }
 
+// DebugBundle generates a debug bundle, uploads it, and returns the upload key.
+// It works both with and without a running engine.
+func (c *Client) DebugBundle(platformFiles PlatformFiles, anonymize bool) (string, error) {
+	cfg, cacheDir, cc := c.stateSnapshot()
+
+	// If the engine hasn't been started, load config from disk
+	if cfg == nil {
+		var err error
+		cfg, err = profilemanager.UpdateOrCreateConfig(profilemanager.ConfigInput{
+			ConfigPath: platformFiles.ConfigurationFilePath(),
+		})
+		if err != nil {
+			return "", fmt.Errorf("load config: %w", err)
+		}
+		cacheDir = platformFiles.CacheDir()
+	}
+
+	deps := debug.GeneratorDependencies{
+		InternalConfig: cfg,
+		StatusRecorder: c.recorder,
+		TempDir:        cacheDir,
+	}
+
+	if cc != nil {
+		resp, err := cc.GetLatestSyncResponse()
+		if err != nil {
+			log.Warnf("get latest sync response: %v", err)
+		}
+		deps.SyncResponse = resp
+
+		if e := cc.Engine(); e != nil {
+			if cm := e.GetClientMetrics(); cm != nil {
+				deps.ClientMetrics = cm
+			}
+		}
+	}
+
+	bundleGenerator := debug.NewBundleGenerator(
+		deps,
+		debug.BundleConfig{
+			Anonymize:         anonymize,
+			IncludeSystemInfo: true,
+		},
+	)
+
+	path, err := bundleGenerator.Generate()
+	if err != nil {
+		return "", fmt.Errorf("generate debug bundle: %w", err)
+	}
+	defer func() {
+		if err := os.Remove(path); err != nil {
+			log.Errorf("failed to remove debug bundle file: %v", err)
+		}
+	}()
+
+	uploadCtx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
+	defer cancel()
+
+	key, err := debug.UploadDebugBundle(uploadCtx, types.DefaultBundleURL, cfg.ManagementURL.String(), path)
+	if err != nil {
+		return "", fmt.Errorf("upload debug bundle: %w", err)
+	}
+
+	log.Infof("debug bundle uploaded with key %s", key)
+	return key, nil
+}
+
 // SetTraceLogLevel configure the logger to trace level
 func (c *Client) SetTraceLogLevel() {
 	log.SetLevel(log.TraceLevel)
@@ -214,12 +312,13 @@ func (c *Client) PeersList() *PeerInfoArray {
 }
 
 func (c *Client) Networks() *NetworkArray {
-	if c.connectClient == nil {
+	cc := c.getConnectClient()
+	if cc == nil {
 		log.Error("not connected")
 		return nil
 	}
 
-	engine := c.connectClient.Engine()
+	engine := cc.Engine()
 	if engine == nil {
 		log.Error("could not get engine")
 		return nil
@@ -300,7 +399,7 @@ func (c *Client) toggleRoute(command routeCommand) error {
 }
 
 func (c *Client) getRouteManager() (routemanager.Manager, error) {
-	client := c.connectClient
+	client := c.getConnectClient()
 	if client == nil {
 		return nil, fmt.Errorf("not connected")
 	}

client/android/platform_files.go

@@ -7,4 +7,5 @@ package android
 type PlatformFiles interface {
 	ConfigurationFilePath() string
 	StateFilePath() string
+	CacheDir() string
 }

client/cmd/capture.go

@@ -0,0 +1,196 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strings"
+	"syscall"
+
+	"github.com/hashicorp/go-multierror"
+	"github.com/spf13/cobra"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/durationpb"
+
+	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/proto"
+	"github.com/netbirdio/netbird/util/capture"
+)
+
+var captureCmd = &cobra.Command{
+	Use:   "capture",
+	Short: "Capture packets on the WireGuard interface",
+	Long: `Captures decrypted packets flowing through the WireGuard interface.
+
+Default output is human-readable text. Use --pcap or --output for pcap binary.
+Requires --enable-capture to be set at service install or reconfigure time.
+
+Examples:
+  netbird debug capture
+  netbird debug capture host 100.64.0.1 and port 443
+  netbird debug capture tcp
+  netbird debug capture icmp
+  netbird debug capture src host 10.0.0.1 and dst port 80
+  netbird debug capture -o capture.pcap
+  netbird debug capture --pcap | tshark -r -
+  netbird debug capture --pcap | tcpdump -r - -n`,
+	Args: cobra.ArbitraryArgs,
+	RunE: runCapture,
+}
+
+func init() {
+	debugCmd.AddCommand(captureCmd)
+
+	captureCmd.Flags().Bool("pcap", false, "Force pcap binary output (default when --output is set)")
+	captureCmd.Flags().BoolP("verbose", "v", false, "Show seq/ack, TTL, window, total length")
+	captureCmd.Flags().Bool("ascii", false, "Print payload as ASCII after each packet (useful for HTTP)")
+	captureCmd.Flags().Uint32("snap-len", 0, "Max bytes per packet (0 = full)")
+	captureCmd.Flags().DurationP("duration", "d", 0, "Capture duration (0 = until interrupted)")
+	captureCmd.Flags().StringP("output", "o", "", "Write pcap to file instead of stdout")
+}
+
+func runCapture(cmd *cobra.Command, args []string) error {
+	conn, err := getClient(cmd)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := conn.Close(); err != nil {
+			cmd.PrintErrf(errCloseConnection, err)
+		}
+	}()
+
+	client := proto.NewDaemonServiceClient(conn)
+
+	req, err := buildCaptureRequest(cmd, args)
+	if err != nil {
+		return err
+	}
+
+	ctx, cancel := signal.NotifyContext(cmd.Context(), syscall.SIGINT, syscall.SIGTERM)
+	defer cancel()
+
+	stream, err := client.StartCapture(ctx, req)
+	if err != nil {
+		return handleCaptureError(err)
+	}
+
+	// First Recv is the empty acceptance message from the server. If the
+	// device is unavailable (kernel WG, not connected, capture disabled),
+	// the server returns an error instead.
+	if _, err := stream.Recv(); err != nil {
+		return handleCaptureError(err)
+	}
+
+	out, cleanup, err := captureOutput(cmd)
+	if err != nil {
+		return err
+	}
+
+	if req.TextOutput {
+		cmd.PrintErrf("Capturing packets... Press Ctrl+C to stop.\n")
+	} else {
+		cmd.PrintErrf("Capturing packets (pcap)... Press Ctrl+C to stop.\n")
+	}
+
+	streamErr := streamCapture(ctx, cmd, stream, out)
+	cleanupErr := cleanup()
+	if streamErr != nil {
+		return streamErr
+	}
+	return cleanupErr
+}
+
+func buildCaptureRequest(cmd *cobra.Command, args []string) (*proto.StartCaptureRequest, error) {
+	req := &proto.StartCaptureRequest{}
+
+	if len(args) > 0 {
+		expr := strings.Join(args, " ")
+		if _, err := capture.ParseFilter(expr); err != nil {
+			return nil, fmt.Errorf("invalid filter: %w", err)
+		}
+		req.FilterExpr = expr
+	}
+
+	if snap, _ := cmd.Flags().GetUint32("snap-len"); snap > 0 {
+		req.SnapLen = snap
+	}
+	if d, _ := cmd.Flags().GetDuration("duration"); d != 0 {
+		if d < 0 {
+			return nil, fmt.Errorf("duration must not be negative")
+		}
+		req.Duration = durationpb.New(d)
+	}
+	req.Verbose, _ = cmd.Flags().GetBool("verbose")
+	req.Ascii, _ = cmd.Flags().GetBool("ascii")
+
+	outPath, _ := cmd.Flags().GetString("output")
+	forcePcap, _ := cmd.Flags().GetBool("pcap")
+	req.TextOutput = !forcePcap && outPath == ""
+
+	return req, nil
+}
+
+func streamCapture(ctx context.Context, cmd *cobra.Command, stream proto.DaemonService_StartCaptureClient, out io.Writer) error {
+	for {
+		pkt, err := stream.Recv()
+		if err != nil {
+			if ctx.Err() != nil {
+				cmd.PrintErrf("\nCapture stopped.\n")
+				return nil //nolint:nilerr // user interrupted
+			}
+			if err == io.EOF {
+				cmd.PrintErrf("\nCapture finished.\n")
+				return nil
+			}
+			return handleCaptureError(err)
+		}
+		if _, err := out.Write(pkt.GetData()); err != nil {
+			return fmt.Errorf("write output: %w", err)
+		}
+	}
+}
+
+// captureOutput returns the writer for capture data and a cleanup function
+// that finalizes the file. Errors from the cleanup must be propagated.
+func captureOutput(cmd *cobra.Command) (io.Writer, func() error, error) {
+	outPath, _ := cmd.Flags().GetString("output")
+	if outPath == "" {
+		return os.Stdout, func() error { return nil }, nil
+	}
+
+	f, err := os.CreateTemp(filepath.Dir(outPath), filepath.Base(outPath)+".*.tmp")
+	if err != nil {
+		return nil, nil, fmt.Errorf("create output file: %w", err)
+	}
+	tmpPath := f.Name()
+	return f, func() error {
+		var merr *multierror.Error
+		if err := f.Close(); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("close output file: %w", err))
+		}
+		fi, statErr := os.Stat(tmpPath)
+		if statErr != nil || fi.Size() == 0 {
+			if rmErr := os.Remove(tmpPath); rmErr != nil && !os.IsNotExist(rmErr) {
+				merr = multierror.Append(merr, fmt.Errorf("remove empty output file: %w", rmErr))
+			}
+			return nberrors.FormatErrorOrNil(merr)
+		}
+		if err := os.Rename(tmpPath, outPath); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("rename output file: %w", err))
+			return nberrors.FormatErrorOrNil(merr)
+		}
+		cmd.PrintErrf("Wrote %s\n", outPath)
+		return nberrors.FormatErrorOrNil(merr)
+	}, nil
+}
+
+func handleCaptureError(err error) error {
+	if s, ok := status.FromError(err); ok {
+		return fmt.Errorf("%s", s.Message())
+	}
+	return err
+}

client/cmd/debug.go

@@ -9,6 +9,7 @@ import (
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/durationpb"
 
 	"github.com/netbirdio/netbird/client/internal"
 	"github.com/netbirdio/netbird/client/internal/debug"
@@ -199,9 +200,11 @@ func runForDuration(cmd *cobra.Command, args []string) error {
 		cmd.Println("Log level set to trace.")
 	}
 
+	needsRestoreUp := false
 	if _, err := client.Down(cmd.Context(), &proto.DownRequest{}); err != nil {
 		cmd.PrintErrf("Failed to bring service down: %v\n", status.Convert(err).Message())
 	} else {
+		needsRestoreUp = !stateWasDown
 		cmd.Println("netbird down")
 	}
 
@@ -217,6 +220,7 @@ func runForDuration(cmd *cobra.Command, args []string) error {
 	if _, err := client.Up(cmd.Context(), &proto.UpRequest{}); err != nil {
 		cmd.PrintErrf("Failed to bring service up: %v\n", status.Convert(err).Message())
 	} else {
+		needsRestoreUp = false
 		cmd.Println("netbird up")
 	}
 
@@ -236,11 +240,50 @@ func runForDuration(cmd *cobra.Command, args []string) error {
 		}()
 	}
 
+	captureStarted := false
+	if wantCapture, _ := cmd.Flags().GetBool("capture"); wantCapture {
+		captureTimeout := duration + 30*time.Second
+		const maxBundleCapture = 10 * time.Minute
+		if captureTimeout > maxBundleCapture {
+			captureTimeout = maxBundleCapture
+		}
+		_, err := client.StartBundleCapture(cmd.Context(), &proto.StartBundleCaptureRequest{
+			Timeout: durationpb.New(captureTimeout),
+		})
+		if err != nil {
+			cmd.PrintErrf("Failed to start packet capture: %v\n", status.Convert(err).Message())
+		} else {
+			captureStarted = true
+			cmd.Println("Packet capture started.")
+			// Safety: always stop on exit, even if the normal stop below runs too.
+			defer func() {
+				if captureStarted {
+					stopCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+					defer cancel()
+					if _, err := client.StopBundleCapture(stopCtx, &proto.StopBundleCaptureRequest{}); err != nil {
+						cmd.PrintErrf("Failed to stop packet capture: %v\n", err)
+					}
+				}
+			}()
+		}
+	}
+
 	if waitErr := waitForDurationOrCancel(cmd.Context(), duration, cmd); waitErr != nil {
 		return waitErr
 	}
 	cmd.Println("\nDuration completed")
 
+	if captureStarted {
+		stopCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		if _, err := client.StopBundleCapture(stopCtx, &proto.StopBundleCaptureRequest{}); err != nil {
+			cmd.PrintErrf("Failed to stop packet capture: %v\n", err)
+		} else {
+			captureStarted = false
+			cmd.Println("Packet capture stopped.")
+		}
+	}
+
 	if cpuProfilingStarted {
 		if _, err := client.StopCPUProfile(cmd.Context(), &proto.StopCPUProfileRequest{}); err != nil {
 			cmd.PrintErrf("Failed to stop CPU profiling: %v\n", err)
@@ -264,6 +307,14 @@ func runForDuration(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("failed to bundle debug: %v", status.Convert(err).Message())
 	}
 
+	if needsRestoreUp {
+		if _, err := client.Up(cmd.Context(), &proto.UpRequest{}); err != nil {
+			cmd.PrintErrf("Failed to restore service up state: %v\n", status.Convert(err).Message())
+		} else {
+			cmd.Println("netbird up (restored)")
+		}
+	}
+
 	if stateWasDown {
 		if _, err := client.Down(cmd.Context(), &proto.DownRequest{}); err != nil {
 			cmd.PrintErrf("Failed to restore service down state: %v\n", status.Convert(err).Message())
@@ -405,4 +456,5 @@ func init() {
 	forCmd.Flags().BoolVarP(&systemInfoFlag, "system-info", "S", true, "Adds system information to the debug bundle")
 	forCmd.Flags().BoolVarP(&uploadBundleFlag, "upload-bundle", "U", false, "Uploads the debug bundle to a server")
 	forCmd.Flags().StringVar(&uploadBundleURLFlag, "upload-bundle-url", types.DefaultBundleURL, "Service URL to get an URL to upload the debug bundle")
+	forCmd.Flags().Bool("capture", false, "Capture packets during the debug duration and include in bundle")
 }

client/cmd/expose.go

@@ -14,6 +14,7 @@ import (
 
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"google.golang.org/grpc/status"
 
 	"github.com/netbirdio/netbird/client/internal/expose"
 	"github.com/netbirdio/netbird/client/proto"
@@ -201,7 +202,7 @@ func exposeFn(cmd *cobra.Command, args []string) error {
 
 	stream, err := client.ExposeService(ctx, req)
 	if err != nil {
-		return fmt.Errorf("expose service: %w", err)
+		return fmt.Errorf("expose service: %v", status.Convert(err).Message())
 	}
 
 	if err := handleExposeReady(cmd, stream, port); err != nil {
@@ -236,7 +237,7 @@ func toExposeProtocol(exposeProtocol string) (proto.ExposeProtocol, error) {
 func handleExposeReady(cmd *cobra.Command, stream proto.DaemonService_ExposeServiceClient, port uint64) error {
 	event, err := stream.Recv()
 	if err != nil {
-		return fmt.Errorf("receive expose event: %w", err)
+		return fmt.Errorf("receive expose event: %v", status.Convert(err).Message())
 	}
 
 	ready, ok := event.Event.(*proto.ExposeServiceEvent_Ready)

client/cmd/login.go

@@ -10,6 +10,7 @@ import (
 
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"golang.org/x/term"
 	"google.golang.org/grpc/codes"
 	gstatus "google.golang.org/grpc/status"
 
@@ -23,6 +24,7 @@ import (
 
 func init() {
 	loginCmd.PersistentFlags().BoolVar(&noBrowser, noBrowserFlag, false, noBrowserDesc)
+	loginCmd.PersistentFlags().BoolVar(&showQR, showQRFlag, false, showQRDesc)
 	loginCmd.PersistentFlags().StringVar(&profileName, profileNameFlag, "", profileNameDesc)
 	loginCmd.PersistentFlags().StringVarP(&configPath, "config", "c", "", "(DEPRECATED) Netbird config file location")
 }
@@ -256,7 +258,7 @@ func doForegroundLogin(ctx context.Context, cmd *cobra.Command, setupKey string,
 }
 
 func handleSSOLogin(ctx context.Context, cmd *cobra.Command, loginResp *proto.LoginResponse, client proto.DaemonServiceClient, pm *profilemanager.ProfileManager) error {
-	openURL(cmd, loginResp.VerificationURIComplete, loginResp.UserCode, noBrowser)
+	openURL(cmd, loginResp.VerificationURIComplete, loginResp.UserCode, noBrowser, showQR)
 
 	resp, err := client.WaitSSOLogin(ctx, &proto.WaitSSOLoginRequest{UserCode: loginResp.UserCode, Hostname: hostName})
 	if err != nil {
@@ -324,7 +326,7 @@ func foregroundGetTokenInfo(ctx context.Context, cmd *cobra.Command, config *pro
 		return nil, fmt.Errorf("getting a request OAuth flow info failed: %v", err)
 	}
 
-	openURL(cmd, flowInfo.VerificationURIComplete, flowInfo.UserCode, noBrowser)
+	openURL(cmd, flowInfo.VerificationURIComplete, flowInfo.UserCode, noBrowser, showQR)
 
 	tokenInfo, err := oAuthFlow.WaitToken(context.TODO(), flowInfo)
 	if err != nil {
@@ -334,7 +336,7 @@ func foregroundGetTokenInfo(ctx context.Context, cmd *cobra.Command, config *pro
 	return &tokenInfo, nil
 }
 
-func openURL(cmd *cobra.Command, verificationURIComplete, userCode string, noBrowser bool) {
+func openURL(cmd *cobra.Command, verificationURIComplete, userCode string, noBrowser, showQR bool) {
 	var codeMsg string
 	if userCode != "" && !strings.Contains(verificationURIComplete, userCode) {
 		codeMsg = fmt.Sprintf("and enter the code %s to authenticate.", userCode)
@@ -348,6 +350,12 @@ func openURL(cmd *cobra.Command, verificationURIComplete, userCode string, noBro
 			verificationURIComplete + " " + codeMsg)
 	}
 
+	if showQR {
+		if f, ok := cmd.OutOrStdout().(*os.File); ok && term.IsTerminal(int(f.Fd())) {
+			printQRCode(f, verificationURIComplete)
+		}
+	}
+
 	cmd.Println("")
 
 	if !noBrowser {

client/cmd/qr.go

@@ -0,0 +1,25 @@
+package cmd
+
+import (
+	"io"
+
+	"github.com/mdp/qrterminal/v3"
+)
+
+// printQRCode prints a QR code for the given URL to the writer.
+// Called only when the user explicitly requests QR output via --qr.
+func printQRCode(w io.Writer, url string) {
+	if url == "" {
+		return
+	}
+	qrterminal.GenerateWithConfig(url, qrterminal.Config{
+		Level:          qrterminal.M,
+		Writer:         w,
+		HalfBlocks:     true,
+		BlackChar:      qrterminal.BLACK_BLACK,
+		WhiteChar:      qrterminal.WHITE_WHITE,
+		BlackWhiteChar: qrterminal.BLACK_WHITE,
+		WhiteBlackChar: qrterminal.WHITE_BLACK,
+		QuietZone:      qrterminal.QUIET_ZONE,
+	})
+}

client/cmd/qr_test.go

@@ -0,0 +1,26 @@
+package cmd
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestPrintQRCode_EmptyURL(t *testing.T) {
+	var buf bytes.Buffer
+
+	printQRCode(&buf, "")
+
+	if buf.Len() != 0 {
+		t.Error("expected no output for empty URL")
+	}
+}
+
+func TestPrintQRCode_WritesOutput(t *testing.T) {
+	var buf bytes.Buffer
+
+	printQRCode(&buf, "https://example.com/auth")
+
+	if buf.Len() == 0 {
+		t.Error("expected QR code output for non-empty URL")
+	}
+}

client/cmd/root.go

@@ -75,6 +75,8 @@ var (
 	mtu                     uint16
 	profilesDisabled        bool
 	updateSettingsDisabled  bool
+	captureEnabled          bool
+	networksDisabled        bool
 
 	rootCmd = &cobra.Command{
 		Use:          "netbird",

client/cmd/service.go

@@ -44,10 +44,14 @@ func init() {
 	serviceCmd.AddCommand(runCmd, startCmd, stopCmd, restartCmd, svcStatusCmd, installCmd, uninstallCmd, reconfigureCmd, resetParamsCmd)
 	serviceCmd.PersistentFlags().BoolVar(&profilesDisabled, "disable-profiles", false, "Disables profiles feature. If enabled, the client will not be able to change or edit any profile. To persist this setting, use: netbird service install --disable-profiles")
 	serviceCmd.PersistentFlags().BoolVar(&updateSettingsDisabled, "disable-update-settings", false, "Disables update settings feature. If enabled, the client will not be able to change or edit any settings. To persist this setting, use: netbird service install --disable-update-settings")
+	serviceCmd.PersistentFlags().BoolVar(&captureEnabled, "enable-capture", false, "Enables packet capture via 'netbird debug capture'. To persist, use: netbird service install --enable-capture")
+	serviceCmd.PersistentFlags().BoolVar(&networksDisabled, "disable-networks", false, "Disables network selection. If enabled, the client will not allow listing, selecting, or deselecting networks. To persist, use: netbird service install --disable-networks")
 
 	rootCmd.PersistentFlags().StringVarP(&serviceName, "service", "s", defaultServiceName, "Netbird system service name")
 	serviceEnvDesc := `Sets extra environment variables for the service. ` +
 		`You can specify a comma-separated list of KEY=VALUE pairs. ` +
+		`New keys are merged with previously saved env vars; existing keys are overwritten. ` +
+		`Use --service-env "" to clear all saved env vars. ` +
 		`E.g. --service-env NB_LOG_LEVEL=debug,CUSTOM_VAR=value`
 
 	installCmd.Flags().StringSliceVar(&serviceEnvVars, "service-env", nil, serviceEnvDesc)

client/cmd/service_controller.go

@@ -61,7 +61,7 @@ func (p *program) Start(svc service.Service) error {
 			}
 		}
 
-		serverInstance := server.New(p.ctx, util.FindFirstLogPath(logFiles), configPath, profilesDisabled, updateSettingsDisabled)
+		serverInstance := server.New(p.ctx, util.FindFirstLogPath(logFiles), configPath, profilesDisabled, updateSettingsDisabled, captureEnabled, networksDisabled)
 		if err := serverInstance.Start(); err != nil {
 			log.Fatalf("failed to start daemon: %v", err)
 		}

client/cmd/service_installer.go

@@ -59,6 +59,14 @@ func buildServiceArguments() []string {
 		args = append(args, "--disable-update-settings")
 	}
 
+	if captureEnabled {
+		args = append(args, "--enable-capture")
+	}
+
+	if networksDisabled {
+		args = append(args, "--disable-networks")
+	}
+
 	return args
 }
 

client/cmd/service_params.go

@@ -28,6 +28,8 @@ type serviceParams struct {
 	LogFiles              []string          `json:"log_files,omitempty"`
 	DisableProfiles       bool              `json:"disable_profiles,omitempty"`
 	DisableUpdateSettings bool              `json:"disable_update_settings,omitempty"`
+	EnableCapture         bool              `json:"enable_capture,omitempty"`
+	DisableNetworks       bool              `json:"disable_networks,omitempty"`
 	ServiceEnvVars        map[string]string `json:"service_env_vars,omitempty"`
 }
 
@@ -78,11 +80,13 @@ func currentServiceParams() *serviceParams {
 		LogFiles:              logFiles,
 		DisableProfiles:       profilesDisabled,
 		DisableUpdateSettings: updateSettingsDisabled,
+		EnableCapture:         captureEnabled,
+		DisableNetworks:       networksDisabled,
 	}
 
 	if len(serviceEnvVars) > 0 {
 		parsed, err := parseServiceEnvVars(serviceEnvVars)
-		if err == nil && len(parsed) > 0 {
+		if err == nil {
 			params.ServiceEnvVars = parsed
 		}
 	}
@@ -142,31 +146,50 @@ func applyServiceParams(cmd *cobra.Command, params *serviceParams) {
 		updateSettingsDisabled = params.DisableUpdateSettings
 	}
 
+	if !serviceCmd.PersistentFlags().Changed("enable-capture") {
+		captureEnabled = params.EnableCapture
+	}
+
+	if !serviceCmd.PersistentFlags().Changed("disable-networks") {
+		networksDisabled = params.DisableNetworks
+	}
+
 	applyServiceEnvParams(cmd, params)
 }
 
 // applyServiceEnvParams merges saved service environment variables.
-// If --service-env was explicitly set, explicit values win on key conflict
-// but saved keys not in the explicit set are carried over.
+// If --service-env was explicitly set with values, explicit values win on key
+// conflict but saved keys not in the explicit set are carried over.
+// If --service-env was explicitly set to empty, all saved env vars are cleared.
 // If --service-env was not set, saved env vars are used entirely.
 func applyServiceEnvParams(cmd *cobra.Command, params *serviceParams) {
-	if len(params.ServiceEnvVars) == 0 {
-		return
-	}
-
 	if !cmd.Flags().Changed("service-env") {
-		// No explicit env vars: rebuild serviceEnvVars from saved params.
-		serviceEnvVars = envMapToSlice(params.ServiceEnvVars)
+		if len(params.ServiceEnvVars) > 0 {
+			// No explicit env vars: rebuild serviceEnvVars from saved params.
+			serviceEnvVars = envMapToSlice(params.ServiceEnvVars)
+		}
 		return
 	}
 
-	// Explicit env vars were provided: merge saved values underneath.
+	// Flag was explicitly set: parse what the user provided.
 	explicit, err := parseServiceEnvVars(serviceEnvVars)
 	if err != nil {
 		cmd.PrintErrf("Warning: parse explicit service env vars for merge: %v\n", err)
 		return
 	}
 
+	// If the user passed an empty value (e.g. --service-env ""), clear all
+	// saved env vars rather than merging.
+	if len(explicit) == 0 {
+		serviceEnvVars = nil
+		return
+	}
+
+	if len(params.ServiceEnvVars) == 0 {
+		return
+	}
+
+	// Merge saved values underneath explicit ones.
 	merged := make(map[string]string, len(params.ServiceEnvVars)+len(explicit))
 	maps.Copy(merged, params.ServiceEnvVars)
 	maps.Copy(merged, explicit) // explicit wins on conflict

client/cmd/service_params_test.go

@@ -327,6 +327,41 @@ func TestApplyServiceEnvParams_NotChanged(t *testing.T) {
 	assert.Equal(t, map[string]string{"FROM_SAVED": "val"}, result)
 }
 
+func TestApplyServiceEnvParams_ExplicitEmptyClears(t *testing.T) {
+	origServiceEnvVars := serviceEnvVars
+	t.Cleanup(func() { serviceEnvVars = origServiceEnvVars })
+
+	// Simulate --service-env "" which produces [""] in the slice.
+	serviceEnvVars = []string{""}
+
+	cmd := &cobra.Command{}
+	cmd.Flags().StringSlice("service-env", nil, "")
+	require.NoError(t, cmd.Flags().Set("service-env", ""))
+
+	saved := &serviceParams{
+		ServiceEnvVars: map[string]string{"OLD_VAR": "should_be_cleared"},
+	}
+
+	applyServiceEnvParams(cmd, saved)
+
+	assert.Nil(t, serviceEnvVars, "explicit empty --service-env should clear all saved env vars")
+}
+
+func TestCurrentServiceParams_EmptyEnvVarsAfterParse(t *testing.T) {
+	origServiceEnvVars := serviceEnvVars
+	t.Cleanup(func() { serviceEnvVars = origServiceEnvVars })
+
+	// Simulate --service-env "" which produces [""] in the slice.
+	serviceEnvVars = []string{""}
+
+	params := currentServiceParams()
+
+	// After parsing, the empty string is skipped, resulting in an empty map.
+	// The map should still be set (not nil) so it overwrites saved values.
+	assert.NotNil(t, params.ServiceEnvVars, "empty env vars should produce empty map, not nil")
+	assert.Empty(t, params.ServiceEnvVars, "no valid env vars should be parsed from empty string")
+}
+
 // TestServiceParams_FieldsCoveredInFunctions ensures that all serviceParams fields are
 // referenced in both currentServiceParams() and applyServiceParams(). If a new field is
 // added to serviceParams but not wired into these functions, this test fails.
@@ -500,6 +535,8 @@ func fieldToGlobalVar(field string) string {
 		"LogFiles":              "logFiles",
 		"DisableProfiles":       "profilesDisabled",
 		"DisableUpdateSettings": "updateSettingsDisabled",
+		"EnableCapture":         "captureEnabled",
+		"DisableNetworks":       "networksDisabled",
 		"ServiceEnvVars":        "serviceEnvVars",
 	}
 	if v, ok := m[field]; ok {

client/cmd/service_test.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"os/signal"
 	"runtime"
+	"syscall"
 	"testing"
 	"time"
 
@@ -13,6 +15,22 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// TestMain intercepts when this test binary is run as a daemon subprocess.
+// On FreeBSD, the rc.d service script runs the binary via daemon(8) -r with
+// "service run ..." arguments. Since the test binary can't handle cobra CLI
+// args, it exits immediately, causing daemon -r to respawn rapidly until
+// hitting the rate limit and exiting. This makes service restart unreliable.
+// Blocking here keeps the subprocess alive until the init system sends SIGTERM.
+func TestMain(m *testing.M) {
+	if len(os.Args) > 2 && os.Args[1] == "service" && os.Args[2] == "run" {
+		sig := make(chan os.Signal, 1)
+		signal.Notify(sig, syscall.SIGTERM, os.Interrupt)
+		<-sig
+		return
+	}
+	os.Exit(m.Run())
+}
+
 const (
 	serviceStartTimeout = 10 * time.Second
 	serviceStopTimeout  = 5 * time.Second
@@ -79,6 +97,34 @@ func TestServiceLifecycle(t *testing.T) {
 	logLevel = "info"
 	daemonAddr = fmt.Sprintf("unix://%s/netbird-test.sock", tempDir)
 
+	// Ensure cleanup even if a subtest fails and Stop/Uninstall subtests don't run.
+	t.Cleanup(func() {
+		cfg, err := newSVCConfig()
+		if err != nil {
+			t.Errorf("cleanup: create service config: %v", err)
+			return
+		}
+		ctxSvc, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		s, err := newSVC(newProgram(ctxSvc, cancel), cfg)
+		if err != nil {
+			t.Errorf("cleanup: create service: %v", err)
+			return
+		}
+
+		// If the subtests already cleaned up, there's nothing to do.
+		if _, err := s.Status(); err != nil {
+			return
+		}
+
+		if err := s.Stop(); err != nil {
+			t.Errorf("cleanup: stop service: %v", err)
+		}
+		if err := s.Uninstall(); err != nil {
+			t.Errorf("cleanup: uninstall service: %v", err)
+		}
+	})
+
 	ctx := context.Background()
 
 	t.Run("Install", func(t *testing.T) {

client/cmd/testutil_test.go

@@ -13,6 +13,8 @@ import (
 
 	"github.com/netbirdio/management-integrations/integrations"
 
+	nbcache "github.com/netbirdio/netbird/management/server/cache"
+
 	"github.com/netbirdio/netbird/management/internals/controllers/network_map/controller"
 	"github.com/netbirdio/netbird/management/internals/controllers/network_map/update_channel"
 	"github.com/netbirdio/netbird/management/internals/modules/peers"
@@ -100,9 +102,16 @@ func startManagement(t *testing.T, config *config.Config, testFile string) (*grp
 
 	jobManager := job.NewJobManager(nil, store, peersmanager)
 
-	iv, _ := integrations.NewIntegratedValidator(context.Background(), peersmanager, settingsManagerMock, eventStore)
+	ctx := context.Background()
 
-	metrics, err := telemetry.NewDefaultAppMetrics(context.Background())
+	cacheStore, err := nbcache.NewStore(ctx, 100*time.Millisecond, 300*time.Millisecond, 100)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	iv, _ := integrations.NewIntegratedValidator(ctx, peersmanager, settingsManagerMock, eventStore, cacheStore)
+
+	metrics, err := telemetry.NewDefaultAppMetrics(ctx)
 	require.NoError(t, err)
 
 	settingsMockManager := settings.NewMockManager(ctrl)
@@ -113,12 +122,11 @@ func startManagement(t *testing.T, config *config.Config, testFile string) (*grp
 		Return(&types.Settings{}, nil).
 		AnyTimes()
 
-	ctx := context.Background()
 	updateManager := update_channel.NewPeersUpdateManager(metrics)
 	requestBuffer := mgmt.NewAccountRequestBuffer(ctx, store)
 	networkMapController := controller.NewController(ctx, store, metrics, updateManager, requestBuffer, mgmt.MockIntegratedValidator{}, settingsMockManager, "netbird.cloud", port_forwarding.NewControllerMock(), manager.NewEphemeralManager(store, peersmanager), config)
 
-	accountManager, err := mgmt.BuildManager(context.Background(), config, store, networkMapController, jobManager, nil, "", eventStore, nil, false, iv, metrics, port_forwarding.NewControllerMock(), settingsMockManager, permissionsManagerMock, false)
+	accountManager, err := mgmt.BuildManager(ctx, config, store, networkMapController, jobManager, nil, "", eventStore, nil, false, iv, metrics, port_forwarding.NewControllerMock(), settingsMockManager, permissionsManagerMock, false, cacheStore)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -127,7 +135,7 @@ func startManagement(t *testing.T, config *config.Config, testFile string) (*grp
 	if err != nil {
 		t.Fatal(err)
 	}
-	mgmtServer, err := nbgrpc.NewServer(config, accountManager, settingsMockManager, jobManager, secretsManager, nil, nil, &mgmt.MockIntegratedValidator{}, networkMapController, nil)
+	mgmtServer, err := nbgrpc.NewServer(config, accountManager, settingsMockManager, jobManager, secretsManager, nil, nil, &mgmt.MockIntegratedValidator{}, networkMapController, nil, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -152,7 +160,7 @@ func startClientDaemon(
 	s := grpc.NewServer()
 
 	server := client.New(ctx,
-		"", "", false, false)
+		"", "", false, false, false, false)
 	if err := server.Start(); err != nil {
 		t.Fatal(err)
 	}

client/cmd/up.go

@@ -39,6 +39,9 @@ const (
 	noBrowserFlag = "no-browser"
 	noBrowserDesc = "do not open the browser for SSO login"
 
+	showQRFlag = "qr"
+	showQRDesc = "show QR code for the SSO login URL (useful for headless machines without browser access)"
+
 	profileNameFlag = "profile"
 	profileNameDesc = "profile name to use for the login. If not specified, the last used profile will be used."
 )
@@ -48,6 +51,7 @@ var (
 	dnsLabels          []string
 	dnsLabelsValidated domain.List
 	noBrowser          bool
+	showQR             bool
 	profileName        string
 	configPath         string
 
@@ -80,6 +84,7 @@ func init() {
 	)
 
 	upCmd.PersistentFlags().BoolVar(&noBrowser, noBrowserFlag, false, noBrowserDesc)
+	upCmd.PersistentFlags().BoolVar(&showQR, showQRFlag, false, showQRDesc)
 	upCmd.PersistentFlags().StringVar(&profileName, profileNameFlag, "", profileNameDesc)
 	upCmd.PersistentFlags().StringVarP(&configPath, "config", "c", "", "(DEPRECATED) NetBird config file location. ")
 

client/embed/capture.go

@@ -0,0 +1,65 @@
+package embed
+
+import (
+	"io"
+
+	"github.com/netbirdio/netbird/client/internal"
+	"github.com/netbirdio/netbird/util/capture"
+)
+
+// CaptureOptions configures a packet capture session.
+type CaptureOptions struct {
+	// Output receives pcap-formatted data. Nil disables pcap output.
+	Output io.Writer
+	// TextOutput receives human-readable packet summaries. Nil disables text output.
+	TextOutput io.Writer
+	// Filter is a BPF-like filter expression (e.g. "host 10.0.0.1 and tcp port 443").
+	// Empty captures all packets.
+	Filter string
+	// Verbose adds seq/ack, TTL, window, and total length to text output.
+	Verbose bool
+	// ASCII dumps transport payload as printable ASCII after each packet line.
+	ASCII bool
+}
+
+// CaptureStats reports capture session counters.
+type CaptureStats struct {
+	Packets int64
+	Bytes   int64
+	Dropped int64
+}
+
+// CaptureSession represents an active packet capture. Call Stop to end the
+// capture and flush buffered packets.
+type CaptureSession struct {
+	sess   *capture.Session
+	engine *internal.Engine
+}
+
+// Stop ends the capture, flushes remaining packets, and detaches from the device.
+// Safe to call multiple times.
+func (cs *CaptureSession) Stop() {
+	if cs.engine != nil {
+		_ = cs.engine.SetCapture(nil)
+		cs.engine = nil
+	}
+	if cs.sess != nil {
+		cs.sess.Stop()
+	}
+}
+
+// Stats returns current capture counters.
+func (cs *CaptureSession) Stats() CaptureStats {
+	s := cs.sess.Stats()
+	return CaptureStats{
+		Packets: s.Packets,
+		Bytes:   s.Bytes,
+		Dropped: s.Dropped,
+	}
+}
+
+// Done returns a channel that is closed when the capture's writer goroutine
+// has fully exited and all buffered packets have been flushed.
+func (cs *CaptureSession) Done() <-chan struct{} {
+	return cs.sess.Done()
+}

client/embed/embed.go

@@ -24,6 +24,7 @@ import (
 	"github.com/netbirdio/netbird/client/system"
 	"github.com/netbirdio/netbird/shared/management/domain"
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
+	"github.com/netbirdio/netbird/util/capture"
 )
 
 var (
@@ -65,7 +66,7 @@ type Options struct {
 	PrivateKey string
 	// ManagementURL overrides the default management server URL
 	ManagementURL string
-	// PreSharedKey is the pre-shared key for the WireGuard interface
+	// PreSharedKey is the pre-shared key for the tunnel interface
 	PreSharedKey string
 	// LogOutput is the output destination for logs (defaults to os.Stderr if nil)
 	LogOutput io.Writer
@@ -81,9 +82,9 @@ type Options struct {
 	DisableClientRoutes bool
 	// BlockInbound blocks all inbound connections from peers
 	BlockInbound bool
-	// WireguardPort is the port for the WireGuard interface. Use 0 for a random port.
+	// WireguardPort is the port for the tunnel interface. Use 0 for a random port.
 	WireguardPort *int
-	// MTU is the MTU for the WireGuard interface.
+	// MTU is the MTU for the tunnel interface.
 	// Valid values are in the range 576..8192 bytes.
 	// If non-nil, this value overrides any value stored in the config file.
 	// If nil, the existing config MTU (if non-zero) is preserved; otherwise it defaults to 1280.
@@ -469,6 +470,52 @@ func (c *Client) VerifySSHHostKey(peerAddress string, key []byte) error {
 	return sshcommon.VerifyHostKey(storedKey, key, peerAddress)
 }
 
+// StartCapture begins capturing packets on this client's tunnel device.
+// Only one capture can be active at a time; starting a new one stops the previous.
+// Call StopCapture (or CaptureSession.Stop) to end it.
+func (c *Client) StartCapture(opts CaptureOptions) (*CaptureSession, error) {
+	engine, err := c.getEngine()
+	if err != nil {
+		return nil, err
+	}
+
+	var matcher capture.Matcher
+	if opts.Filter != "" {
+		m, err := capture.ParseFilter(opts.Filter)
+		if err != nil {
+			return nil, fmt.Errorf("parse filter: %w", err)
+		}
+		matcher = m
+	}
+
+	sess, err := capture.NewSession(capture.Options{
+		Output:     opts.Output,
+		TextOutput: opts.TextOutput,
+		Matcher:    matcher,
+		Verbose:    opts.Verbose,
+		ASCII:      opts.ASCII,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("create capture session: %w", err)
+	}
+
+	if err := engine.SetCapture(sess); err != nil {
+		sess.Stop()
+		return nil, fmt.Errorf("set capture: %w", err)
+	}
+
+	return &CaptureSession{sess: sess, engine: engine}, nil
+}
+
+// StopCapture stops the active capture session if one is running.
+func (c *Client) StopCapture() error {
+	engine, err := c.getEngine()
+	if err != nil {
+		return err
+	}
+	return engine.SetCapture(nil)
+}
+
 // getEngine safely retrieves the engine from the client with proper locking.
 // Returns ErrClientNotStarted if the client is not started.
 // Returns ErrEngineNotStarted if the engine is not available.

client/firewall/create_linux.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"strconv"
 
 	"github.com/coreos/go-iptables/iptables"
 	"github.com/google/nftables"
@@ -35,20 +36,34 @@ const SKIP_NFTABLES_ENV = "NB_SKIP_NFTABLES_CHECK"
 type FWType int
 
 func NewFirewall(iface IFaceMapper, stateManager *statemanager.Manager, flowLogger nftypes.FlowLogger, disableServerRoutes bool, mtu uint16) (firewall.Manager, error) {
-	// on the linux system we try to user nftables or iptables
-	// in any case, because we need to allow netbird interface traffic
-	// so we use AllowNetbird traffic from these firewall managers
-	// for the userspace packet filtering firewall
+	// We run in userspace mode and force userspace firewall was requested. We don't attempt native firewall.
+	if iface.IsUserspaceBind() && forceUserspaceFirewall() {
+		log.Info("forcing userspace firewall")
+		return createUserspaceFirewall(iface, nil, disableServerRoutes, flowLogger, mtu)
+	}
+
+	// Use native firewall for either kernel or userspace, the interface appears identical to netfilter
 	fm, err := createNativeFirewall(iface, stateManager, disableServerRoutes, mtu)
 
+	// Kernel cannot fall back to anything else, need to return error
 	if !iface.IsUserspaceBind() {
 		return fm, err
 	}
 
+	// Fall back to the userspace packet filter if native is unavailable
 	if err != nil {
 		log.Warnf("failed to create native firewall: %v. Proceeding with userspace", err)
+		return createUserspaceFirewall(iface, nil, disableServerRoutes, flowLogger, mtu)
 	}
-	return createUserspaceFirewall(iface, fm, disableServerRoutes, flowLogger, mtu)
+
+	// Native firewall handles packet filtering, but the userspace WireGuard bind
+	// needs a device filter for DNS interception hooks. Install a minimal
+	// hooks-only filter that passes all traffic through to the kernel firewall.
+	if err := iface.SetFilter(&uspfilter.HooksFilter{}); err != nil {
+		log.Warnf("failed to set hooks filter, DNS via memory hooks will not work: %v", err)
+	}
+
+	return fm, nil
 }
 
 func createNativeFirewall(iface IFaceMapper, stateManager *statemanager.Manager, routes bool, mtu uint16) (firewall.Manager, error) {
@@ -160,3 +175,17 @@ func isIptablesClientAvailable(client *iptables.IPTables) bool {
 	_, err := client.ListChains("filter")
 	return err == nil
 }
+
+func forceUserspaceFirewall() bool {
+	val := os.Getenv(EnvForceUserspaceFirewall)
+	if val == "" {
+		return false
+	}
+
+	force, err := strconv.ParseBool(val)
+	if err != nil {
+		log.Warnf("failed to parse %s: %v", EnvForceUserspaceFirewall, err)
+		return false
+	}
+	return force
+}

client/firewall/firewalld/firewalld.go

@@ -0,0 +1,11 @@
+// Package firewalld integrates with the firewalld daemon so NetBird can place
+// its wg interface into firewalld's "trusted" zone. This is required because
+// firewalld's nftables chains are created with NFT_CHAIN_OWNER on recent
+// versions, which returns EPERM to any other process that tries to insert
+// rules into them. The workaround mirrors what Tailscale does: let firewalld
+// itself add the accept rules to its own chains by trusting the interface.
+package firewalld
+
+// TrustedZone is the firewalld zone name used for interfaces whose traffic
+// should bypass firewalld filtering.
+const TrustedZone = "trusted"

client/firewall/firewalld/firewalld_linux.go

@@ -0,0 +1,260 @@
+//go:build linux
+
+package firewalld
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/godbus/dbus/v5"
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	dbusDest      = "org.fedoraproject.FirewallD1"
+	dbusPath      = "/org/fedoraproject/FirewallD1"
+	dbusRootIface = "org.fedoraproject.FirewallD1"
+	dbusZoneIface = "org.fedoraproject.FirewallD1.zone"
+
+	errZoneAlreadySet = "ZONE_ALREADY_SET"
+	errAlreadyEnabled = "ALREADY_ENABLED"
+	errUnknownIface   = "UNKNOWN_INTERFACE"
+	errNotEnabled     = "NOT_ENABLED"
+
+	// callTimeout bounds each individual DBus or firewall-cmd invocation.
+	// A fresh context is created for each call so a slow DBus probe can't
+	// exhaust the deadline before the firewall-cmd fallback gets to run.
+	callTimeout = 3 * time.Second
+)
+
+var (
+	errDBusUnavailable = errors.New("firewalld dbus unavailable")
+
+	// trustLogOnce ensures the "added to trusted zone" message is logged at
+	// Info level only for the first successful add per process; repeat adds
+	// from other init paths are quieter.
+	trustLogOnce sync.Once
+
+	parentCtxMu sync.RWMutex
+	parentCtx   context.Context = context.Background()
+)
+
+// SetParentContext installs a parent context whose cancellation aborts any
+// in-flight TrustInterface call. It does not affect UntrustInterface, which
+// always uses a fresh Background-rooted timeout so cleanup can still run
+// during engine shutdown when the engine context is already cancelled.
+func SetParentContext(ctx context.Context) {
+	parentCtxMu.Lock()
+	parentCtx = ctx
+	parentCtxMu.Unlock()
+}
+
+func getParentContext() context.Context {
+	parentCtxMu.RLock()
+	defer parentCtxMu.RUnlock()
+	return parentCtx
+}
+
+// TrustInterface places iface into firewalld's trusted zone if firewalld is
+// running. It is idempotent and best-effort: errors are returned so callers
+// can log, but a non-running firewalld is not an error. Only the first
+// successful call per process logs at Info. Respects the parent context set
+// via SetParentContext so startup-time cancellation unblocks it.
+func TrustInterface(iface string) error {
+	parent := getParentContext()
+	if !isRunning(parent) {
+		return nil
+	}
+	if err := addTrusted(parent, iface); err != nil {
+		return fmt.Errorf("add %s to firewalld trusted zone: %w", iface, err)
+	}
+	trustLogOnce.Do(func() {
+		log.Infof("added %s to firewalld trusted zone", iface)
+	})
+	log.Debugf("firewalld: ensured %s is in trusted zone", iface)
+	return nil
+}
+
+// UntrustInterface removes iface from firewalld's trusted zone if firewalld
+// is running. Idempotent. Uses a Background-rooted timeout so it still runs
+// during shutdown after the engine context has been cancelled.
+func UntrustInterface(iface string) error {
+	if !isRunning(context.Background()) {
+		return nil
+	}
+	if err := removeTrusted(context.Background(), iface); err != nil {
+		return fmt.Errorf("remove %s from firewalld trusted zone: %w", iface, err)
+	}
+	return nil
+}
+
+func newCallContext(parent context.Context) (context.Context, context.CancelFunc) {
+	return context.WithTimeout(parent, callTimeout)
+}
+
+func isRunning(parent context.Context) bool {
+	ctx, cancel := newCallContext(parent)
+	ok, err := isRunningDBus(ctx)
+	cancel()
+	if err == nil {
+		return ok
+	}
+	if errors.Is(err, errDBusUnavailable) || errors.Is(err, context.DeadlineExceeded) {
+		ctx, cancel = newCallContext(parent)
+		defer cancel()
+		return isRunningCLI(ctx)
+	}
+	return false
+}
+
+func addTrusted(parent context.Context, iface string) error {
+	ctx, cancel := newCallContext(parent)
+	err := addDBus(ctx, iface)
+	cancel()
+	if err == nil {
+		return nil
+	}
+	if !errors.Is(err, errDBusUnavailable) {
+		log.Debugf("firewalld: dbus add failed, falling back to firewall-cmd: %v", err)
+	}
+	ctx, cancel = newCallContext(parent)
+	defer cancel()
+	return addCLI(ctx, iface)
+}
+
+func removeTrusted(parent context.Context, iface string) error {
+	ctx, cancel := newCallContext(parent)
+	err := removeDBus(ctx, iface)
+	cancel()
+	if err == nil {
+		return nil
+	}
+	if !errors.Is(err, errDBusUnavailable) {
+		log.Debugf("firewalld: dbus remove failed, falling back to firewall-cmd: %v", err)
+	}
+	ctx, cancel = newCallContext(parent)
+	defer cancel()
+	return removeCLI(ctx, iface)
+}
+
+func isRunningDBus(ctx context.Context) (bool, error) {
+	conn, err := dbus.SystemBus()
+	if err != nil {
+		return false, fmt.Errorf("%w: %v", errDBusUnavailable, err)
+	}
+	obj := conn.Object(dbusDest, dbusPath)
+
+	var zone string
+	if err := obj.CallWithContext(ctx, dbusRootIface+".getDefaultZone", 0).Store(&zone); err != nil {
+		return false, fmt.Errorf("firewalld getDefaultZone: %w", err)
+	}
+	return true, nil
+}
+
+func isRunningCLI(ctx context.Context) bool {
+	if _, err := exec.LookPath("firewall-cmd"); err != nil {
+		return false
+	}
+	return exec.CommandContext(ctx, "firewall-cmd", "--state").Run() == nil
+}
+
+func addDBus(ctx context.Context, iface string) error {
+	conn, err := dbus.SystemBus()
+	if err != nil {
+		return fmt.Errorf("%w: %v", errDBusUnavailable, err)
+	}
+	obj := conn.Object(dbusDest, dbusPath)
+
+	call := obj.CallWithContext(ctx, dbusZoneIface+".addInterface", 0, TrustedZone, iface)
+	if call.Err == nil {
+		return nil
+	}
+
+	if dbusErrContains(call.Err, errAlreadyEnabled) {
+		return nil
+	}
+
+	if dbusErrContains(call.Err, errZoneAlreadySet) {
+		move := obj.CallWithContext(ctx, dbusZoneIface+".changeZoneOfInterface", 0, TrustedZone, iface)
+		if move.Err != nil {
+			return fmt.Errorf("firewalld changeZoneOfInterface: %w", move.Err)
+		}
+		return nil
+	}
+
+	return fmt.Errorf("firewalld addInterface: %w", call.Err)
+}
+
+func removeDBus(ctx context.Context, iface string) error {
+	conn, err := dbus.SystemBus()
+	if err != nil {
+		return fmt.Errorf("%w: %v", errDBusUnavailable, err)
+	}
+	obj := conn.Object(dbusDest, dbusPath)
+
+	call := obj.CallWithContext(ctx, dbusZoneIface+".removeInterface", 0, TrustedZone, iface)
+	if call.Err == nil {
+		return nil
+	}
+
+	if dbusErrContains(call.Err, errUnknownIface) || dbusErrContains(call.Err, errNotEnabled) {
+		return nil
+	}
+
+	return fmt.Errorf("firewalld removeInterface: %w", call.Err)
+}
+
+func addCLI(ctx context.Context, iface string) error {
+	if _, err := exec.LookPath("firewall-cmd"); err != nil {
+		return fmt.Errorf("firewall-cmd not available: %w", err)
+	}
+
+	// --change-interface (no --permanent) binds the interface for the
+	// current runtime only; we do not want membership to persist across
+	// reboots because netbird re-asserts it on every startup.
+	out, err := exec.CommandContext(ctx,
+		"firewall-cmd", "--zone="+TrustedZone, "--change-interface="+iface,
+	).CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("firewall-cmd change-interface: %w: %s", err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
+func removeCLI(ctx context.Context, iface string) error {
+	if _, err := exec.LookPath("firewall-cmd"); err != nil {
+		return fmt.Errorf("firewall-cmd not available: %w", err)
+	}
+
+	out, err := exec.CommandContext(ctx,
+		"firewall-cmd", "--zone="+TrustedZone, "--remove-interface="+iface,
+	).CombinedOutput()
+	if err != nil {
+		msg := strings.TrimSpace(string(out))
+		if strings.Contains(msg, errUnknownIface) || strings.Contains(msg, errNotEnabled) {
+			return nil
+		}
+		return fmt.Errorf("firewall-cmd remove-interface: %w: %s", err, msg)
+	}
+	return nil
+}
+
+func dbusErrContains(err error, code string) bool {
+	if err == nil {
+		return false
+	}
+	var de dbus.Error
+	if errors.As(err, &de) {
+		for _, b := range de.Body {
+			if s, ok := b.(string); ok && strings.Contains(s, code) {
+				return true
+			}
+		}
+	}
+	return strings.Contains(err.Error(), code)
+}

client/firewall/firewalld/firewalld_linux_test.go

@@ -0,0 +1,49 @@
+//go:build linux
+
+package firewalld
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/godbus/dbus/v5"
+)
+
+func TestDBusErrContains(t *testing.T) {
+	tests := []struct {
+		name string
+		err  error
+		code string
+		want bool
+	}{
+		{"nil error", nil, errZoneAlreadySet, false},
+		{"plain error match", errors.New("ZONE_ALREADY_SET: wt0"), errZoneAlreadySet, true},
+		{"plain error miss", errors.New("something else"), errZoneAlreadySet, false},
+		{
+			"dbus.Error body match",
+			dbus.Error{Name: "org.fedoraproject.FirewallD1.Exception", Body: []any{"ZONE_ALREADY_SET: wt0"}},
+			errZoneAlreadySet,
+			true,
+		},
+		{
+			"dbus.Error body miss",
+			dbus.Error{Name: "org.fedoraproject.FirewallD1.Exception", Body: []any{"INVALID_INTERFACE"}},
+			errAlreadyEnabled,
+			false,
+		},
+		{
+			"dbus.Error non-string body falls back to Error()",
+			dbus.Error{Name: "x", Body: []any{123}},
+			"x",
+			true,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := dbusErrContains(tc.err, tc.code)
+			if got != tc.want {
+				t.Fatalf("dbusErrContains(%v, %q) = %v; want %v", tc.err, tc.code, got, tc.want)
+			}
+		})
+	}
+}

client/firewall/firewalld/firewalld_other.go

@@ -0,0 +1,25 @@
+//go:build !linux
+
+package firewalld
+
+import "context"
+
+// SetParentContext is a no-op on non-Linux platforms because firewalld only
+// runs on Linux.
+func SetParentContext(context.Context) {
+	// intentionally empty: firewalld is a Linux-only daemon
+}
+
+// TrustInterface is a no-op on non-Linux platforms because firewalld only
+// runs on Linux.
+func TrustInterface(string) error {
+	// intentionally empty: firewalld is a Linux-only daemon
+	return nil
+}
+
+// UntrustInterface is a no-op on non-Linux platforms because firewalld only
+// runs on Linux.
+func UntrustInterface(string) error {
+	// intentionally empty: firewalld is a Linux-only daemon
+	return nil
+}

client/firewall/iface.go

@@ -7,6 +7,12 @@ import (
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 )
 
+// EnvForceUserspaceFirewall forces the use of the userspace packet filter even when
+// native iptables/nftables is available. This only applies when the WireGuard interface
+// runs in userspace mode. When set, peer ACLs are handled by USPFilter instead of
+// kernel netfilter rules.
+const EnvForceUserspaceFirewall = "NB_FORCE_USERSPACE_FIREWALL"
+
 // IFaceMapper defines subset methods of interface required for manager
 type IFaceMapper interface {
 	Name() string

client/firewall/iptables/acl_linux.go

@@ -21,6 +21,10 @@ const (
 
 	// rules chains contains the effective ACL rules
 	chainNameInputRules = "NETBIRD-ACL-INPUT"
+
+	// mangleFwdKey is the entries map key for mangle FORWARD guard rules that prevent
+	// external DNAT from bypassing ACL rules.
+	mangleFwdKey = "MANGLE-FORWARD"
 )
 
 type aclEntries map[string][][]string
@@ -274,6 +278,12 @@ func (m *aclManager) cleanChains() error {
 		}
 	}
 
+	for _, rule := range m.entries[mangleFwdKey] {
+		if err := m.iptablesClient.DeleteIfExists(tableMangle, chainFORWARD, rule...); err != nil {
+			log.Errorf("failed to delete mangle FORWARD guard rule: %v, %s", rule, err)
+		}
+	}
+
 	for _, ipsetName := range m.ipsetStore.ipsetNames() {
 		if err := m.flushIPSet(ipsetName); err != nil {
 			if errors.Is(err, ipset.ErrSetNotExist) {
@@ -303,6 +313,10 @@ func (m *aclManager) createDefaultChains() error {
 	}
 
 	for chainName, rules := range m.entries {
+		// mangle FORWARD guard rules are handled separately below
+		if chainName == mangleFwdKey {
+			continue
+		}
 		for _, rule := range rules {
 			if err := m.iptablesClient.InsertUnique(tableName, chainName, 1, rule...); err != nil {
 				log.Debugf("failed to create input chain jump rule: %s", err)
@@ -322,6 +336,13 @@ func (m *aclManager) createDefaultChains() error {
 	}
 	clear(m.optionalEntries)
 
+	// Insert mangle FORWARD guard rules to prevent external DNAT bypass.
+	for _, rule := range m.entries[mangleFwdKey] {
+		if err := m.iptablesClient.AppendUnique(tableMangle, chainFORWARD, rule...); err != nil {
+			log.Errorf("failed to add mangle FORWARD guard rule: %v", err)
+		}
+	}
+
 	return nil
 }
 
@@ -343,6 +364,22 @@ func (m *aclManager) seedInitialEntries() {
 
 	m.appendToEntries("FORWARD", []string{"-o", m.wgIface.Name(), "-j", chainRTFWDOUT})
 	m.appendToEntries("FORWARD", []string{"-i", m.wgIface.Name(), "-j", chainRTFWDIN})
+
+	// Mangle FORWARD guard: when external DNAT redirects traffic from the wg interface, it
+	// traverses FORWARD instead of INPUT, bypassing ACL rules. ACCEPT rules in filter FORWARD
+	// can be inserted above ours. Mangle runs before filter, so these guard rules enforce the
+	// ACL mark check where it cannot be overridden.
+	m.appendToEntries(mangleFwdKey, []string{
+		"-i", m.wgIface.Name(),
+		"-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED",
+		"-j", "ACCEPT",
+	})
+	m.appendToEntries(mangleFwdKey, []string{
+		"-i", m.wgIface.Name(),
+		"-m", "conntrack", "--ctstate", "DNAT",
+		"-m", "mark", "!", "--mark", fmt.Sprintf("%#x", nbnet.PreroutingFwmarkRedirected),
+		"-j", "DROP",
+	})
 }
 
 func (m *aclManager) seedInitialOptionalEntries() {

client/firewall/iptables/manager_linux.go

@@ -12,6 +12,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/firewall/firewalld"
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
@@ -33,7 +34,6 @@ type Manager struct {
 type iFaceMapper interface {
 	Name() string
 	Address() wgaddr.Address
-	IsUserspaceBind() bool
 }
 
 // Create iptables firewall manager
@@ -64,10 +64,9 @@ func Create(wgIface iFaceMapper, mtu uint16) (*Manager, error) {
 func (m *Manager) Init(stateManager *statemanager.Manager) error {
 	state := &ShutdownState{
 		InterfaceState: &InterfaceState{
-			NameStr:       m.wgIface.Name(),
-			WGAddress:     m.wgIface.Address(),
-			UserspaceBind: m.wgIface.IsUserspaceBind(),
-			MTU:           m.router.mtu,
+			NameStr:   m.wgIface.Name(),
+			WGAddress: m.wgIface.Address(),
+			MTU:       m.router.mtu,
 		},
 	}
 	stateManager.RegisterState(state)
@@ -88,6 +87,12 @@ func (m *Manager) Init(stateManager *statemanager.Manager) error {
 		log.Warnf("raw table not available, notrack rules will be disabled: %v", err)
 	}
 
+	// Trust after all fatal init steps so a later failure doesn't leave the
+	// interface in firewalld's trusted zone without a corresponding Close.
+	if err := firewalld.TrustInterface(m.wgIface.Name()); err != nil {
+		log.Warnf("failed to trust interface in firewalld: %v", err)
+	}
+
 	// persist early to ensure cleanup of chains
 	go func() {
 		if err := stateManager.PersistState(context.Background()); err != nil {
@@ -193,6 +198,12 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 		merr = multierror.Append(merr, fmt.Errorf("reset router: %w", err))
 	}
 
+	// Appending to merr intentionally blocks DeleteState below so ShutdownState
+	// stays persisted and the crash-recovery path retries firewalld cleanup.
+	if err := firewalld.UntrustInterface(m.wgIface.Name()); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
 	// attempt to delete state only if all other operations succeeded
 	if merr == nil {
 		if err := stateManager.DeleteState(&ShutdownState{}); err != nil {
@@ -203,12 +214,10 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 	return nberrors.FormatErrorOrNil(merr)
 }
 
-// AllowNetbird allows netbird interface traffic
+// AllowNetbird allows netbird interface traffic.
+// This is called when USPFilter wraps the native firewall, adding blanket accept
+// rules so that packet filtering is handled in userspace instead of by netfilter.
 func (m *Manager) AllowNetbird() error {
-	if !m.wgIface.IsUserspaceBind() {
-		return nil
-	}
-
 	_, err := m.AddPeerFiltering(
 		nil,
 		net.IP{0, 0, 0, 0},
@@ -221,6 +230,11 @@ func (m *Manager) AllowNetbird() error {
 	if err != nil {
 		return fmt.Errorf("allow netbird interface traffic: %w", err)
 	}
+
+	if err := firewalld.TrustInterface(m.wgIface.Name()); err != nil {
+		log.Warnf("failed to trust interface in firewalld: %v", err)
+	}
+
 	return nil
 }
 
@@ -286,6 +300,22 @@ func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Prot
 	return m.router.RemoveInboundDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
+// AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
+func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	return m.router.AddOutputDNAT(localAddr, protocol, sourcePort, targetPort)
+}
+
+// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
+func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	return m.router.RemoveOutputDNAT(localAddr, protocol, sourcePort, targetPort)
+}
+
 const (
 	chainNameRaw = "NETBIRD-RAW"
 	chainOUTPUT  = "OUTPUT"

client/firewall/iptables/manager_linux_test.go

@@ -47,8 +47,6 @@ func (i *iFaceMock) Address() wgaddr.Address {
 	panic("AddressFunc is not set")
 }
 
-func (i *iFaceMock) IsUserspaceBind() bool { return false }
-
 func TestIptablesManager(t *testing.T) {
 	ipv4Client, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
 	require.NoError(t, err)

client/firewall/iptables/router_linux.go

@@ -36,6 +36,7 @@ const (
 	chainRTFWDOUT           = "NETBIRD-RT-FWD-OUT"
 	chainRTPRE              = "NETBIRD-RT-PRE"
 	chainRTRDR              = "NETBIRD-RT-RDR"
+	chainNATOutput          = "NETBIRD-NAT-OUTPUT"
 	chainRTMSSCLAMP         = "NETBIRD-RT-MSSCLAMP"
 	routingFinalForwardJump = "ACCEPT"
 	routingFinalNatJump     = "MASQUERADE"
@@ -43,6 +44,7 @@ const (
 	jumpManglePre  = "jump-mangle-pre"
 	jumpNatPre     = "jump-nat-pre"
 	jumpNatPost    = "jump-nat-post"
+	jumpNatOutput  = "jump-nat-output"
 	jumpMSSClamp   = "jump-mss-clamp"
 	markManglePre  = "mark-mangle-pre"
 	markManglePost = "mark-mangle-post"
@@ -387,6 +389,14 @@ func (r *router) cleanUpDefaultForwardRules() error {
 	}
 
 	log.Debug("flushing routing related tables")
+
+	// Remove jump rules from built-in chains before deleting custom chains,
+	// otherwise the chain deletion fails with "device or resource busy".
+	jumpRule := []string{"-j", chainNATOutput}
+	if err := r.iptablesClient.Delete(tableNat, "OUTPUT", jumpRule...); err != nil {
+		log.Debugf("clean OUTPUT jump rule: %v", err)
+	}
+
 	for _, chainInfo := range []struct {
 		chain string
 		table string
@@ -396,6 +406,7 @@ func (r *router) cleanUpDefaultForwardRules() error {
 		{chainRTPRE, tableMangle},
 		{chainRTNAT, tableNat},
 		{chainRTRDR, tableNat},
+		{chainNATOutput, tableNat},
 		{chainRTMSSCLAMP, tableMangle},
 	} {
 		ok, err := r.iptablesClient.ChainExists(chainInfo.table, chainInfo.chain)
@@ -970,6 +981,81 @@ func (r *router) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Proto
 	return nil
 }
 
+// ensureNATOutputChain lazily creates the OUTPUT NAT chain and jump rule on first use.
+func (r *router) ensureNATOutputChain() error {
+	if _, exists := r.rules[jumpNatOutput]; exists {
+		return nil
+	}
+
+	chainExists, err := r.iptablesClient.ChainExists(tableNat, chainNATOutput)
+	if err != nil {
+		return fmt.Errorf("check chain %s: %w", chainNATOutput, err)
+	}
+	if !chainExists {
+		if err := r.iptablesClient.NewChain(tableNat, chainNATOutput); err != nil {
+			return fmt.Errorf("create chain %s: %w", chainNATOutput, err)
+		}
+	}
+
+	jumpRule := []string{"-j", chainNATOutput}
+	if err := r.iptablesClient.Insert(tableNat, "OUTPUT", 1, jumpRule...); err != nil {
+		if !chainExists {
+			if delErr := r.iptablesClient.ClearAndDeleteChain(tableNat, chainNATOutput); delErr != nil {
+				log.Warnf("failed to rollback chain %s: %v", chainNATOutput, delErr)
+			}
+		}
+		return fmt.Errorf("add OUTPUT jump rule: %w", err)
+	}
+	r.rules[jumpNatOutput] = jumpRule
+
+	r.updateState()
+	return nil
+}
+
+// AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
+func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
+
+	if _, exists := r.rules[ruleID]; exists {
+		return nil
+	}
+
+	if err := r.ensureNATOutputChain(); err != nil {
+		return err
+	}
+
+	dnatRule := []string{
+		"-p", strings.ToLower(string(protocol)),
+		"--dport", strconv.Itoa(int(sourcePort)),
+		"-d", localAddr.String(),
+		"-j", "DNAT",
+		"--to-destination", ":" + strconv.Itoa(int(targetPort)),
+	}
+
+	if err := r.iptablesClient.Append(tableNat, chainNATOutput, dnatRule...); err != nil {
+		return fmt.Errorf("add output DNAT rule: %w", err)
+	}
+	r.rules[ruleID] = dnatRule
+
+	r.updateState()
+	return nil
+}
+
+// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
+func (r *router) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
+
+	if dnatRule, exists := r.rules[ruleID]; exists {
+		if err := r.iptablesClient.Delete(tableNat, chainNATOutput, dnatRule...); err != nil {
+			return fmt.Errorf("delete output DNAT rule: %w", err)
+		}
+		delete(r.rules, ruleID)
+	}
+
+	r.updateState()
+	return nil
+}
+
 func applyPort(flag string, port *firewall.Port) []string {
 	if port == nil {
 		return nil

client/firewall/iptables/state_linux.go

@@ -9,10 +9,9 @@ import (
 )
 
 type InterfaceState struct {
-	NameStr       string         `json:"name"`
-	WGAddress     wgaddr.Address `json:"wg_address"`
-	UserspaceBind bool           `json:"userspace_bind"`
-	MTU           uint16         `json:"mtu"`
+	NameStr   string         `json:"name"`
+	WGAddress wgaddr.Address `json:"wg_address"`
+	MTU       uint16         `json:"mtu"`
 }
 
 func (i *InterfaceState) Name() string {
@@ -23,10 +22,6 @@ func (i *InterfaceState) Address() wgaddr.Address {
 	return i.WGAddress
 }
 
-func (i *InterfaceState) IsUserspaceBind() bool {
-	return i.UserspaceBind
-}
-
 type ShutdownState struct {
 	sync.Mutex
 

client/firewall/manager/firewall.go

@@ -169,6 +169,14 @@ type Manager interface {
 	// RemoveInboundDNAT removes inbound DNAT rule
 	RemoveInboundDNAT(localAddr netip.Addr, protocol Protocol, sourcePort, targetPort uint16) error
 
+	// AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
+	// localAddr must be IPv4; the underlying iptables/nftables backends are IPv4-only.
+	AddOutputDNAT(localAddr netip.Addr, protocol Protocol, sourcePort, targetPort uint16) error
+
+	// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
+	// localAddr must be IPv4; the underlying iptables/nftables backends are IPv4-only.
+	RemoveOutputDNAT(localAddr netip.Addr, protocol Protocol, sourcePort, targetPort uint16) error
+
 	// SetupEBPFProxyNoTrack creates static notrack rules for eBPF proxy loopback traffic.
 	// This prevents conntrack from interfering with WireGuard proxy communication.
 	SetupEBPFProxyNoTrack(proxyPort, wgPort uint16) error

client/firewall/nftables/manager_linux.go

@@ -14,6 +14,7 @@ import (
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sys/unix"
 
+	"github.com/netbirdio/netbird/client/firewall/firewalld"
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
@@ -40,7 +41,6 @@ func getTableName() string {
 type iFaceMapper interface {
 	Name() string
 	Address() wgaddr.Address
-	IsUserspaceBind() bool
 }
 
 // Manager of iptables firewall
@@ -106,10 +106,9 @@ func (m *Manager) Init(stateManager *statemanager.Manager) error {
 	// cleanup using Close() without needing to store specific rules.
 	if err := stateManager.UpdateState(&ShutdownState{
 		InterfaceState: &InterfaceState{
-			NameStr:       m.wgIface.Name(),
-			WGAddress:     m.wgIface.Address(),
-			UserspaceBind: m.wgIface.IsUserspaceBind(),
-			MTU:           m.router.mtu,
+			NameStr:   m.wgIface.Name(),
+			WGAddress: m.wgIface.Address(),
+			MTU:       m.router.mtu,
 		},
 	}); err != nil {
 		log.Errorf("failed to update state: %v", err)
@@ -205,12 +204,10 @@ func (m *Manager) RemoveNatRule(pair firewall.RouterPair) error {
 	return m.router.RemoveNatRule(pair)
 }
 
-// AllowNetbird allows netbird interface traffic
+// AllowNetbird allows netbird interface traffic.
+// This is called when USPFilter wraps the native firewall, adding blanket accept
+// rules so that packet filtering is handled in userspace instead of by netfilter.
 func (m *Manager) AllowNetbird() error {
-	if !m.wgIface.IsUserspaceBind() {
-		return nil
-	}
-
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
@@ -221,6 +218,10 @@ func (m *Manager) AllowNetbird() error {
 		return fmt.Errorf("flush allow input netbird rules: %w", err)
 	}
 
+	if err := firewalld.TrustInterface(m.wgIface.Name()); err != nil {
+		log.Warnf("failed to trust interface in firewalld: %v", err)
+	}
+
 	return nil
 }
 
@@ -346,6 +347,22 @@ func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Prot
 	return m.router.RemoveInboundDNAT(localAddr, protocol, sourcePort, targetPort)
 }
 
+// AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
+func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	return m.router.AddOutputDNAT(localAddr, protocol, sourcePort, targetPort)
+}
+
+// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
+func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	return m.router.RemoveOutputDNAT(localAddr, protocol, sourcePort, targetPort)
+}
+
 const (
 	chainNameRawOutput     = "netbird-raw-out"
 	chainNameRawPrerouting = "netbird-raw-pre"

client/firewall/nftables/manager_linux_test.go

@@ -52,8 +52,6 @@ func (i *iFaceMock) Address() wgaddr.Address {
 	panic("AddressFunc is not set")
 }
 
-func (i *iFaceMock) IsUserspaceBind() bool { return false }
-
 func TestNftablesManager(t *testing.T) {
 
 	// just check on the local interface

client/firewall/nftables/router_linux.go

@@ -19,6 +19,7 @@ import (
 	"golang.org/x/sys/unix"
 
 	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/firewall/firewalld"
 	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	nbid "github.com/netbirdio/netbird/client/internal/acl/id"
 	"github.com/netbirdio/netbird/client/internal/routemanager/ipfwdstate"
@@ -36,9 +37,12 @@ const (
 	chainNameRoutingFw     = "netbird-rt-fwd"
 	chainNameRoutingNat    = "netbird-rt-postrouting"
 	chainNameRoutingRdr    = "netbird-rt-redirect"
+	chainNameNATOutput     = "netbird-nat-output"
 	chainNameForward       = "FORWARD"
 	chainNameMangleForward = "netbird-mangle-forward"
 
+	firewalldTableName = "firewalld"
+
 	userDataAcceptForwardRuleIif = "frwacceptiif"
 	userDataAcceptForwardRuleOif = "frwacceptoif"
 	userDataAcceptInputRule      = "inputaccept"
@@ -132,6 +136,10 @@ func (r *router) Reset() error {
 		merr = multierror.Append(merr, fmt.Errorf("remove accept filter rules: %w", err))
 	}
 
+	if err := firewalld.UntrustInterface(r.wgIface.Name()); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
 	if err := r.removeNatPreroutingRules(); err != nil {
 		merr = multierror.Append(merr, fmt.Errorf("remove filter prerouting rules: %w", err))
 	}
@@ -279,6 +287,10 @@ func (r *router) createContainers() error {
 		log.Errorf("failed to add accept rules for the forward chain: %s", err)
 	}
 
+	if err := firewalld.TrustInterface(r.wgIface.Name()); err != nil {
+		log.Warnf("failed to trust interface in firewalld: %v", err)
+	}
+
 	if err := r.refreshRulesMap(); err != nil {
 		log.Errorf("failed to refresh rules: %s", err)
 	}
@@ -1318,6 +1330,13 @@ func (r *router) isExternalChain(chain *nftables.Chain) bool {
 		return false
 	}
 
+	// Skip firewalld-owned chains. Firewalld creates its chains with the
+	// NFT_CHAIN_OWNER flag, so inserting rules into them returns EPERM.
+	// We delegate acceptance to firewalld by trusting the interface instead.
+	if chain.Table.Name == firewalldTableName {
+		return false
+	}
+
 	// Skip all iptables-managed tables in the ip family
 	if chain.Table.Family == nftables.TableFamilyIPv4 && isIptablesTable(chain.Table.Name) {
 		return false
@@ -1853,6 +1872,130 @@ func (r *router) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Proto
 	return nil
 }
 
+// ensureNATOutputChain lazily creates the OUTPUT NAT chain on first use.
+func (r *router) ensureNATOutputChain() error {
+	if _, exists := r.chains[chainNameNATOutput]; exists {
+		return nil
+	}
+
+	r.chains[chainNameNATOutput] = r.conn.AddChain(&nftables.Chain{
+		Name:     chainNameNATOutput,
+		Table:    r.workTable,
+		Hooknum:  nftables.ChainHookOutput,
+		Priority: nftables.ChainPriorityNATDest,
+		Type:     nftables.ChainTypeNAT,
+	})
+
+	if err := r.conn.Flush(); err != nil {
+		delete(r.chains, chainNameNATOutput)
+		return fmt.Errorf("create NAT output chain: %w", err)
+	}
+	return nil
+}
+
+// AddOutputDNAT adds an OUTPUT chain DNAT rule for locally-generated traffic.
+func (r *router) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
+
+	if _, exists := r.rules[ruleID]; exists {
+		return nil
+	}
+
+	if err := r.ensureNATOutputChain(); err != nil {
+		return err
+	}
+
+	protoNum, err := protoToInt(protocol)
+	if err != nil {
+		return fmt.Errorf("convert protocol to number: %w", err)
+	}
+
+	exprs := []expr.Any{
+		&expr.Meta{Key: expr.MetaKeyL4PROTO, Register: 1},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 1,
+			Data:     []byte{protoNum},
+		},
+		&expr.Payload{
+			DestRegister: 2,
+			Base:         expr.PayloadBaseTransportHeader,
+			Offset:       2,
+			Len:          2,
+		},
+		&expr.Cmp{
+			Op:       expr.CmpOpEq,
+			Register: 2,
+			Data:     binaryutil.BigEndian.PutUint16(sourcePort),
+		},
+	}
+
+	exprs = append(exprs, applyPrefix(netip.PrefixFrom(localAddr, 32), false)...)
+
+	exprs = append(exprs,
+		&expr.Immediate{
+			Register: 1,
+			Data:     localAddr.AsSlice(),
+		},
+		&expr.Immediate{
+			Register: 2,
+			Data:     binaryutil.BigEndian.PutUint16(targetPort),
+		},
+		&expr.NAT{
+			Type:        expr.NATTypeDestNAT,
+			Family:      uint32(nftables.TableFamilyIPv4),
+			RegAddrMin:  1,
+			RegProtoMin: 2,
+		},
+	)
+
+	dnatRule := &nftables.Rule{
+		Table:    r.workTable,
+		Chain:    r.chains[chainNameNATOutput],
+		Exprs:    exprs,
+		UserData: []byte(ruleID),
+	}
+	r.conn.AddRule(dnatRule)
+
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("add output DNAT rule: %w", err)
+	}
+
+	r.rules[ruleID] = dnatRule
+
+	return nil
+}
+
+// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
+func (r *router) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	if err := r.refreshRulesMap(); err != nil {
+		return fmt.Errorf(refreshRulesMapError, err)
+	}
+
+	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, sourcePort, targetPort)
+
+	rule, exists := r.rules[ruleID]
+	if !exists {
+		return nil
+	}
+
+	if rule.Handle == 0 {
+		log.Warnf("output DNAT rule %s has no handle, removing stale entry", ruleID)
+		delete(r.rules, ruleID)
+		return nil
+	}
+
+	if err := r.conn.DelRule(rule); err != nil {
+		return fmt.Errorf("delete output DNAT rule %s: %w", ruleID, err)
+	}
+	if err := r.conn.Flush(); err != nil {
+		return fmt.Errorf("flush delete output DNAT rule: %w", err)
+	}
+	delete(r.rules, ruleID)
+
+	return nil
+}
+
 // applyNetwork generates nftables expressions for networks (CIDR) or sets
 func (r *router) applyNetwork(
 	network firewall.Network,

client/firewall/nftables/state_linux.go

@@ -8,10 +8,9 @@ import (
 )
 
 type InterfaceState struct {
-	NameStr       string         `json:"name"`
-	WGAddress     wgaddr.Address `json:"wg_address"`
-	UserspaceBind bool           `json:"userspace_bind"`
-	MTU           uint16         `json:"mtu"`
+	NameStr   string         `json:"name"`
+	WGAddress wgaddr.Address `json:"wg_address"`
+	MTU       uint16         `json:"mtu"`
 }
 
 func (i *InterfaceState) Name() string {
@@ -22,10 +21,6 @@ func (i *InterfaceState) Address() wgaddr.Address {
 	return i.WGAddress
 }
 
-func (i *InterfaceState) IsUserspaceBind() bool {
-	return i.UserspaceBind
-}
-
 type ShutdownState struct {
 	InterfaceState *InterfaceState `json:"interface_state,omitempty"`
 }

client/firewall/uspfilter/allow_netbird.go

@@ -3,6 +3,9 @@
 package uspfilter
 
 import (
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/client/firewall/firewalld"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
 )
 
@@ -16,6 +19,9 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 	if m.nativeFirewall != nil {
 		return m.nativeFirewall.Close(stateManager)
 	}
+	if err := firewalld.UntrustInterface(m.wgIface.Name()); err != nil {
+		log.Warnf("failed to untrust interface in firewalld: %v", err)
+	}
 	return nil
 }
 
@@ -24,5 +30,8 @@ func (m *Manager) AllowNetbird() error {
 	if m.nativeFirewall != nil {
 		return m.nativeFirewall.AllowNetbird()
 	}
+	if err := firewalld.TrustInterface(m.wgIface.Name()); err != nil {
+		log.Warnf("failed to trust interface in firewalld: %v", err)
+	}
 	return nil
 }

client/firewall/uspfilter/common/hooks.go

@@ -0,0 +1,37 @@
+package common
+
+import (
+	"net/netip"
+	"sync/atomic"
+)
+
+// PacketHook stores a registered hook for a specific IP:port.
+type PacketHook struct {
+	IP   netip.Addr
+	Port uint16
+	Fn   func([]byte) bool
+}
+
+// HookMatches checks if a packet's destination matches the hook and invokes it.
+func HookMatches(h *PacketHook, dstIP netip.Addr, dport uint16, packetData []byte) bool {
+	if h == nil {
+		return false
+	}
+	if h.IP == dstIP && h.Port == dport {
+		return h.Fn(packetData)
+	}
+	return false
+}
+
+// SetHook atomically stores a hook, handling nil removal.
+func SetHook(ptr *atomic.Pointer[PacketHook], ip netip.Addr, dPort uint16, hook func([]byte) bool) {
+	if hook == nil {
+		ptr.Store(nil)
+		return
+	}
+	ptr.Store(&PacketHook{
+		IP:   ip,
+		Port: dPort,
+		Fn:   hook,
+	})
+}

client/firewall/uspfilter/common/iface.go

@@ -9,6 +9,7 @@ import (
 
 // IFaceMapper defines subset methods of interface required for manager
 type IFaceMapper interface {
+	Name() string
 	SetFilter(device.PacketFilter) error
 	Address() wgaddr.Address
 	GetWGDevice() *wgdevice.Device

client/firewall/uspfilter/filter.go

@@ -115,12 +115,13 @@ type Manager struct {
 
 	localipmanager *localIPManager
 
-	udpTracker  *conntrack.UDPTracker
-	icmpTracker *conntrack.ICMPTracker
-	tcpTracker  *conntrack.TCPTracker
-	forwarder   atomic.Pointer[forwarder.Forwarder]
-	logger      *nblog.Logger
-	flowLogger  nftypes.FlowLogger
+	udpTracker     *conntrack.UDPTracker
+	icmpTracker    *conntrack.ICMPTracker
+	tcpTracker     *conntrack.TCPTracker
+	forwarder      atomic.Pointer[forwarder.Forwarder]
+	pendingCapture atomic.Pointer[forwarder.PacketCapture]
+	logger         *nblog.Logger
+	flowLogger     nftypes.FlowLogger
 
 	blockRule firewall.Rule
 
@@ -140,6 +141,10 @@ type Manager struct {
 	mtu             uint16
 	mssClampValue   uint16
 	mssClampEnabled bool
+
+	// Only one hook per protocol is supported. Outbound direction only.
+	udpHookOut atomic.Pointer[common.PacketHook]
+	tcpHookOut atomic.Pointer[common.PacketHook]
 }
 
 // decoder for packages
@@ -347,6 +352,19 @@ func (m *Manager) determineRouting() error {
 	return nil
 }
 
+// SetPacketCapture sets or clears packet capture on the forwarder endpoint.
+// This captures outbound response packets that bypass the FilteredDevice in netstack mode.
+func (m *Manager) SetPacketCapture(pc forwarder.PacketCapture) {
+	if pc == nil {
+		m.pendingCapture.Store(nil)
+	} else {
+		m.pendingCapture.Store(&pc)
+	}
+	if fwder := m.forwarder.Load(); fwder != nil {
+		fwder.SetCapture(pc)
+	}
+}
+
 // initForwarder initializes the forwarder, it disables routing on errors
 func (m *Manager) initForwarder() error {
 	if m.forwarder.Load() != nil {
@@ -368,6 +386,11 @@ func (m *Manager) initForwarder() error {
 
 	m.forwarder.Store(forwarder)
 
+	// Re-load after store: a concurrent SetPacketCapture may have seen forwarder as nil and only updated pendingCapture.
+	if pc := m.pendingCapture.Load(); pc != nil {
+		forwarder.SetCapture(*pc)
+	}
+
 	log.Debug("forwarder initialized")
 
 	return nil
@@ -594,6 +617,8 @@ func (m *Manager) resetState() {
 	maps.Clear(m.incomingRules)
 	maps.Clear(m.routeRulesMap)
 	m.routeRules = m.routeRules[:0]
+	m.udpHookOut.Store(nil)
+	m.tcpHookOut.Store(nil)
 
 	if m.udpTracker != nil {
 		m.udpTracker.Close()
@@ -608,6 +633,7 @@ func (m *Manager) resetState() {
 	}
 
 	if fwder := m.forwarder.Load(); fwder != nil {
+		fwder.SetCapture(nil)
 		fwder.Stop()
 	}
 
@@ -713,6 +739,9 @@ func (m *Manager) filterOutbound(packetData []byte, size int) bool {
 			return true
 		}
 	case layers.LayerTypeTCP:
+		if m.tcpHooksDrop(uint16(d.tcp.DstPort), dstIP, packetData) {
+			return true
+		}
 		// Clamp MSS on all TCP SYN packets, including those from local IPs.
 		// SNATed routed traffic may appear as local IP but still requires clamping.
 		if m.mssClampEnabled {
@@ -895,39 +924,12 @@ func (m *Manager) trackInbound(d *decoder, srcIP, dstIP netip.Addr, ruleID []byt
 	d.dnatOrigPort = 0
 }
 
-// udpHooksDrop checks if any UDP hooks should drop the packet
 func (m *Manager) udpHooksDrop(dport uint16, dstIP netip.Addr, packetData []byte) bool {
-	m.mutex.RLock()
-	defer m.mutex.RUnlock()
+	return common.HookMatches(m.udpHookOut.Load(), dstIP, dport, packetData)
+}
 
-	// Check specific destination IP first
-	if rules, exists := m.outgoingRules[dstIP]; exists {
-		for _, rule := range rules {
-			if rule.udpHook != nil && portsMatch(rule.dPort, dport) {
-				return rule.udpHook(packetData)
-			}
-		}
-	}
-
-	// Check IPv4 unspecified address
-	if rules, exists := m.outgoingRules[netip.IPv4Unspecified()]; exists {
-		for _, rule := range rules {
-			if rule.udpHook != nil && portsMatch(rule.dPort, dport) {
-				return rule.udpHook(packetData)
-			}
-		}
-	}
-
-	// Check IPv6 unspecified address
-	if rules, exists := m.outgoingRules[netip.IPv6Unspecified()]; exists {
-		for _, rule := range rules {
-			if rule.udpHook != nil && portsMatch(rule.dPort, dport) {
-				return rule.udpHook(packetData)
-			}
-		}
-	}
-
-	return false
+func (m *Manager) tcpHooksDrop(dport uint16, dstIP netip.Addr, packetData []byte) bool {
+	return common.HookMatches(m.tcpHookOut.Load(), dstIP, dport, packetData)
 }
 
 // filterInbound implements filtering logic for incoming packets.
@@ -1278,12 +1280,6 @@ func validateRule(ip netip.Addr, packetData []byte, rules map[string]PeerRule, d
 				return rule.mgmtId, rule.drop, true
 			}
 		case layers.LayerTypeUDP:
-			// if rule has UDP hook (and if we are here we match this rule)
-			// we ignore rule.drop and call this hook
-			if rule.udpHook != nil {
-				return rule.mgmtId, rule.udpHook(packetData), true
-			}
-
 			if portsMatch(rule.sPort, uint16(d.udp.SrcPort)) && portsMatch(rule.dPort, uint16(d.udp.DstPort)) {
 				return rule.mgmtId, rule.drop, true
 			}
@@ -1342,65 +1338,14 @@ func (m *Manager) ruleMatches(rule *RouteRule, srcAddr, dstAddr netip.Addr, prot
 	return sourceMatched
 }
 
-// AddUDPPacketHook calls hook when UDP packet from given direction matched
-//
-// Hook function returns flag which indicates should be the matched package dropped or not
-func (m *Manager) AddUDPPacketHook(in bool, ip netip.Addr, dPort uint16, hook func(packet []byte) bool) string {
-	r := PeerRule{
-		id:         uuid.New().String(),
-		ip:         ip,
-		protoLayer: layers.LayerTypeUDP,
-		dPort:      &firewall.Port{Values: []uint16{dPort}},
-		ipLayer:    layers.LayerTypeIPv6,
-		udpHook:    hook,
-	}
-
-	if ip.Is4() {
-		r.ipLayer = layers.LayerTypeIPv4
-	}
-
-	m.mutex.Lock()
-	if in {
-		// Incoming UDP hooks are stored in allow rules map
-		if _, ok := m.incomingRules[r.ip]; !ok {
-			m.incomingRules[r.ip] = make(map[string]PeerRule)
-		}
-		m.incomingRules[r.ip][r.id] = r
-	} else {
-		if _, ok := m.outgoingRules[r.ip]; !ok {
-			m.outgoingRules[r.ip] = make(map[string]PeerRule)
-		}
-		m.outgoingRules[r.ip][r.id] = r
-	}
-	m.mutex.Unlock()
-
-	return r.id
+// SetUDPPacketHook sets the outbound UDP packet hook. Pass nil hook to remove.
+func (m *Manager) SetUDPPacketHook(ip netip.Addr, dPort uint16, hook func(packet []byte) bool) {
+	common.SetHook(&m.udpHookOut, ip, dPort, hook)
 }
 
-// RemovePacketHook removes packet hook by given ID
-func (m *Manager) RemovePacketHook(hookID string) error {
-	m.mutex.Lock()
-	defer m.mutex.Unlock()
-
-	// Check incoming hooks (stored in allow rules)
-	for _, arr := range m.incomingRules {
-		for _, r := range arr {
-			if r.id == hookID {
-				delete(arr, r.id)
-				return nil
-			}
-		}
-	}
-	// Check outgoing hooks
-	for _, arr := range m.outgoingRules {
-		for _, r := range arr {
-			if r.id == hookID {
-				delete(arr, r.id)
-				return nil
-			}
-		}
-	}
-	return fmt.Errorf("hook with given id not found")
+// SetTCPPacketHook sets the outbound TCP packet hook. Pass nil hook to remove.
+func (m *Manager) SetTCPPacketHook(ip netip.Addr, dPort uint16, hook func(packet []byte) bool) {
+	common.SetHook(&m.tcpHookOut, ip, dPort, hook)
 }
 
 // SetLogLevel sets the log level for the firewall manager

client/firewall/uspfilter/filter_test.go

@@ -12,6 +12,7 @@ import (
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	wgdevice "golang.zx2c4.com/wireguard/device"
 
@@ -30,12 +31,20 @@ var logger = log.NewFromLogrus(logrus.StandardLogger())
 var flowLogger = netflow.NewManager(nil, []byte{}, nil).GetLogger()
 
 type IFaceMock struct {
+	NameFunc        func() string
 	SetFilterFunc   func(device.PacketFilter) error
 	AddressFunc     func() wgaddr.Address
 	GetWGDeviceFunc func() *wgdevice.Device
 	GetDeviceFunc   func() *device.FilteredDevice
 }
 
+func (i *IFaceMock) Name() string {
+	if i.NameFunc == nil {
+		return "wgtest"
+	}
+	return i.NameFunc()
+}
+
 func (i *IFaceMock) GetWGDevice() *wgdevice.Device {
 	if i.GetWGDeviceFunc == nil {
 		return nil
@@ -186,81 +195,52 @@ func TestManagerDeleteRule(t *testing.T) {
 	}
 }
 
-func TestAddUDPPacketHook(t *testing.T) {
-	tests := []struct {
-		name       string
-		in         bool
-		expDir     fw.RuleDirection
-		ip         netip.Addr
-		dPort      uint16
-		hook       func([]byte) bool
-		expectedID string
-	}{
-		{
-			name:   "Test Outgoing UDP Packet Hook",
-			in:     false,
-			expDir: fw.RuleDirectionOUT,
-			ip:     netip.MustParseAddr("10.168.0.1"),
-			dPort:  8000,
-			hook:   func([]byte) bool { return true },
-		},
-		{
-			name:   "Test Incoming UDP Packet Hook",
-			in:     true,
-			expDir: fw.RuleDirectionIN,
-			ip:     netip.MustParseAddr("::1"),
-			dPort:  9000,
-			hook:   func([]byte) bool { return false },
-		},
-	}
+func TestSetUDPPacketHook(t *testing.T) {
+	manager, err := Create(&IFaceMock{
+		SetFilterFunc: func(device.PacketFilter) error { return nil },
+	}, false, flowLogger, nbiface.DefaultMTU)
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, manager.Close(nil)) })
 
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			manager, err := Create(&IFaceMock{
-				SetFilterFunc: func(device.PacketFilter) error { return nil },
-			}, false, flowLogger, nbiface.DefaultMTU)
-			require.NoError(t, err)
+	var called bool
+	manager.SetUDPPacketHook(netip.MustParseAddr("10.168.0.1"), 8000, func([]byte) bool {
+		called = true
+		return true
+	})
 
-			manager.AddUDPPacketHook(tt.in, tt.ip, tt.dPort, tt.hook)
+	h := manager.udpHookOut.Load()
+	require.NotNil(t, h)
+	assert.Equal(t, netip.MustParseAddr("10.168.0.1"), h.IP)
+	assert.Equal(t, uint16(8000), h.Port)
+	assert.True(t, h.Fn(nil))
+	assert.True(t, called)
 
-			var addedRule PeerRule
-			if tt.in {
-				// Incoming UDP hooks are stored in allow rules map
-				if len(manager.incomingRules[tt.ip]) != 1 {
-					t.Errorf("expected 1 incoming rule, got %d", len(manager.incomingRules[tt.ip]))
-					return
-				}
-				for _, rule := range manager.incomingRules[tt.ip] {
-					addedRule = rule
-				}
-			} else {
-				if len(manager.outgoingRules[tt.ip]) != 1 {
-					t.Errorf("expected 1 outgoing rule, got %d", len(manager.outgoingRules[tt.ip]))
-					return
-				}
-				for _, rule := range manager.outgoingRules[tt.ip] {
-					addedRule = rule
-				}
-			}
+	manager.SetUDPPacketHook(netip.MustParseAddr("10.168.0.1"), 8000, nil)
+	assert.Nil(t, manager.udpHookOut.Load())
+}
 
-			if tt.ip.Compare(addedRule.ip) != 0 {
-				t.Errorf("expected ip %s, got %s", tt.ip, addedRule.ip)
-				return
-			}
-			if tt.dPort != addedRule.dPort.Values[0] {
-				t.Errorf("expected dPort %d, got %d", tt.dPort, addedRule.dPort.Values[0])
-				return
-			}
-			if layers.LayerTypeUDP != addedRule.protoLayer {
-				t.Errorf("expected protoLayer %s, got %s", layers.LayerTypeUDP, addedRule.protoLayer)
-				return
-			}
-			if addedRule.udpHook == nil {
-				t.Errorf("expected udpHook to be set")
-				return
-			}
-		})
-	}
+func TestSetTCPPacketHook(t *testing.T) {
+	manager, err := Create(&IFaceMock{
+		SetFilterFunc: func(device.PacketFilter) error { return nil },
+	}, false, flowLogger, nbiface.DefaultMTU)
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, manager.Close(nil)) })
+
+	var called bool
+	manager.SetTCPPacketHook(netip.MustParseAddr("10.168.0.1"), 53, func([]byte) bool {
+		called = true
+		return true
+	})
+
+	h := manager.tcpHookOut.Load()
+	require.NotNil(t, h)
+	assert.Equal(t, netip.MustParseAddr("10.168.0.1"), h.IP)
+	assert.Equal(t, uint16(53), h.Port)
+	assert.True(t, h.Fn(nil))
+	assert.True(t, called)
+
+	manager.SetTCPPacketHook(netip.MustParseAddr("10.168.0.1"), 53, nil)
+	assert.Nil(t, manager.tcpHookOut.Load())
 }
 
 // TestPeerRuleLifecycleDenyRules verifies that deny rules are correctly added
@@ -530,39 +510,12 @@ func TestRemovePacketHook(t *testing.T) {
 		require.NoError(t, manager.Close(nil))
 	}()
 
-	// Add a UDP packet hook
-	hookFunc := func(data []byte) bool { return true }
-	hookID := manager.AddUDPPacketHook(false, netip.MustParseAddr("192.168.0.1"), 8080, hookFunc)
+	manager.SetUDPPacketHook(netip.MustParseAddr("192.168.0.1"), 8080, func([]byte) bool { return true })
 
-	// Assert the hook is added by finding it in the manager's outgoing rules
-	found := false
-	for _, arr := range manager.outgoingRules {
-		for _, rule := range arr {
-			if rule.id == hookID {
-				found = true
-				break
-			}
-		}
-	}
+	require.NotNil(t, manager.udpHookOut.Load(), "hook should be registered")
 
-	if !found {
-		t.Fatalf("The hook was not added properly.")
-	}
-
-	// Now remove the packet hook
-	err = manager.RemovePacketHook(hookID)
-	if err != nil {
-		t.Fatalf("Failed to remove hook: %s", err)
-	}
-
-	// Assert the hook is removed by checking it in the manager's outgoing rules
-	for _, arr := range manager.outgoingRules {
-		for _, rule := range arr {
-			if rule.id == hookID {
-				t.Fatalf("The hook was not removed properly.")
-			}
-		}
-	}
+	manager.SetUDPPacketHook(netip.MustParseAddr("192.168.0.1"), 8080, nil)
+	assert.Nil(t, manager.udpHookOut.Load(), "hook should be removed")
 }
 
 func TestProcessOutgoingHooks(t *testing.T) {
@@ -592,8 +545,7 @@ func TestProcessOutgoingHooks(t *testing.T) {
 	}
 
 	hookCalled := false
-	hookID := manager.AddUDPPacketHook(
-		false,
+	manager.SetUDPPacketHook(
 		netip.MustParseAddr("100.10.0.100"),
 		53,
 		func([]byte) bool {
@@ -601,7 +553,6 @@ func TestProcessOutgoingHooks(t *testing.T) {
 			return true
 		},
 	)
-	require.NotEmpty(t, hookID)
 
 	// Create test UDP packet
 	ipv4 := &layers.IPv4{

client/firewall/uspfilter/forwarder/endpoint.go

@@ -12,12 +12,19 @@ import (
 	nblog "github.com/netbirdio/netbird/client/firewall/uspfilter/log"
 )
 
+// PacketCapture captures raw packets for debugging. Implementations must be
+// safe for concurrent use and must not block.
+type PacketCapture interface {
+	Offer(data []byte, outbound bool)
+}
+
 // endpoint implements stack.LinkEndpoint and handles integration with the wireguard device
 type endpoint struct {
 	logger     *nblog.Logger
 	dispatcher stack.NetworkDispatcher
 	device     *wgdevice.Device
 	mtu        atomic.Uint32
+	capture    atomic.Pointer[PacketCapture]
 }
 
 func (e *endpoint) Attach(dispatcher stack.NetworkDispatcher) {
@@ -54,13 +61,17 @@ func (e *endpoint) WritePackets(pkts stack.PacketBufferList) (int, tcpip.Error)
 			continue
 		}
 
-		// Send the packet through WireGuard
+		pktBytes := data.AsSlice()
+
 		address := netHeader.DestinationAddress()
-		err := e.device.CreateOutboundPacket(data.AsSlice(), address.AsSlice())
-		if err != nil {
+		if err := e.device.CreateOutboundPacket(pktBytes, address.AsSlice()); err != nil {
 			e.logger.Error1("CreateOutboundPacket: %v", err)
 			continue
 		}
+
+		if pc := e.capture.Load(); pc != nil {
+			(*pc).Offer(pktBytes, true)
+		}
 		written++
 	}
 

client/firewall/uspfilter/forwarder/forwarder.go

@@ -139,6 +139,16 @@ func New(iface common.IFaceMapper, logger *nblog.Logger, flowLogger nftypes.Flow
 	return f, nil
 }
 
+// SetCapture sets or clears the packet capture on the forwarder endpoint.
+// This captures outbound packets that bypass the FilteredDevice (netstack forwarding).
+func (f *Forwarder) SetCapture(pc PacketCapture) {
+	if pc == nil {
+		f.endpoint.capture.Store(nil)
+		return
+	}
+	f.endpoint.capture.Store(&pc)
+}
+
 func (f *Forwarder) InjectIncomingPacket(payload []byte) error {
 	if len(payload) < header.IPv4MinimumSize {
 		return fmt.Errorf("packet too small: %d bytes", len(payload))

client/firewall/uspfilter/forwarder/icmp.go

@@ -270,5 +270,9 @@ func (f *Forwarder) injectICMPReply(id stack.TransportEndpointID, icmpPayload []
 		return 0
 	}
 
+	if pc := f.endpoint.capture.Load(); pc != nil {
+		(*pc).Offer(fullPacket, true)
+	}
+
 	return len(fullPacket)
 }

client/firewall/uspfilter/hooks_filter.go

@@ -0,0 +1,90 @@
+package uspfilter
+
+import (
+	"encoding/binary"
+	"net/netip"
+	"sync/atomic"
+
+	"github.com/netbirdio/netbird/client/firewall/uspfilter/common"
+	"github.com/netbirdio/netbird/client/iface/device"
+)
+
+const (
+	ipv4HeaderMinLen = 20
+	ipv4ProtoOffset  = 9
+	ipv4FlagsOffset  = 6
+	ipv4DstOffset    = 16
+	ipProtoUDP       = 17
+	ipProtoTCP       = 6
+	ipv4FragOffMask  = 0x1fff
+	// dstPortOffset is the offset of the destination port within a UDP or TCP header.
+	dstPortOffset = 2
+)
+
+// HooksFilter is a minimal packet filter that only handles outbound DNS hooks.
+// It is installed on the WireGuard interface when the userspace bind is active
+// but a full firewall filter (Manager) is not needed because a native kernel
+// firewall (nftables/iptables) handles packet filtering.
+type HooksFilter struct {
+	udpHook atomic.Pointer[common.PacketHook]
+	tcpHook atomic.Pointer[common.PacketHook]
+}
+
+var _ device.PacketFilter = (*HooksFilter)(nil)
+
+// FilterOutbound checks outbound packets for DNS hook matches.
+// Only IPv4 packets matching the registered hook IP:port are intercepted.
+// IPv6 and non-IP packets pass through unconditionally.
+func (f *HooksFilter) FilterOutbound(packetData []byte, _ int) bool {
+	if len(packetData) < ipv4HeaderMinLen {
+		return false
+	}
+
+	// Only process IPv4 packets, let everything else pass through.
+	if packetData[0]>>4 != 4 {
+		return false
+	}
+
+	ihl := int(packetData[0]&0x0f) * 4
+	if ihl < ipv4HeaderMinLen || len(packetData) < ihl+4 {
+		return false
+	}
+
+	// Skip non-first fragments: they don't carry L4 headers.
+	flagsAndOffset := binary.BigEndian.Uint16(packetData[ipv4FlagsOffset : ipv4FlagsOffset+2])
+	if flagsAndOffset&ipv4FragOffMask != 0 {
+		return false
+	}
+
+	dstIP, ok := netip.AddrFromSlice(packetData[ipv4DstOffset : ipv4DstOffset+4])
+	if !ok {
+		return false
+	}
+
+	proto := packetData[ipv4ProtoOffset]
+	dstPort := binary.BigEndian.Uint16(packetData[ihl+dstPortOffset : ihl+dstPortOffset+2])
+
+	switch proto {
+	case ipProtoUDP:
+		return common.HookMatches(f.udpHook.Load(), dstIP, dstPort, packetData)
+	case ipProtoTCP:
+		return common.HookMatches(f.tcpHook.Load(), dstIP, dstPort, packetData)
+	default:
+		return false
+	}
+}
+
+// FilterInbound allows all inbound packets (native firewall handles filtering).
+func (f *HooksFilter) FilterInbound([]byte, int) bool {
+	return false
+}
+
+// SetUDPPacketHook registers the UDP packet hook.
+func (f *HooksFilter) SetUDPPacketHook(ip netip.Addr, dPort uint16, hook func([]byte) bool) {
+	common.SetHook(&f.udpHook, ip, dPort, hook)
+}
+
+// SetTCPPacketHook registers the TCP packet hook.
+func (f *HooksFilter) SetTCPPacketHook(ip netip.Addr, dPort uint16, hook func([]byte) bool) {
+	common.SetHook(&f.tcpHook, ip, dPort, hook)
+}

client/firewall/uspfilter/localip.go

@@ -144,6 +144,8 @@ func (m *localIPManager) UpdateLocalIPs(iface common.IFaceMapper) (err error) {
 	if err != nil {
 		log.Warnf("failed to get interfaces: %v", err)
 	} else {
+		// TODO: filter out down interfaces (net.FlagUp). Also handle the reverse
+		// case where an interface comes up between refreshes.
 		for _, intf := range interfaces {
 			m.processInterface(intf, &newIPv4Bitmap, ipv4Set, &ipv4Addresses)
 		}

client/firewall/uspfilter/nat.go

@@ -421,6 +421,7 @@ func (m *Manager) addPortRedirection(targetIP netip.Addr, protocol gopacket.Laye
 }
 
 // AddInboundDNAT adds an inbound DNAT rule redirecting traffic from NetBird peers to local services.
+// TODO: also delegate to nativeFirewall when available for kernel WG mode
 func (m *Manager) AddInboundDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
 	var layerType gopacket.LayerType
 	switch protocol {
@@ -466,6 +467,22 @@ func (m *Manager) RemoveInboundDNAT(localAddr netip.Addr, protocol firewall.Prot
 	return m.removePortRedirection(localAddr, layerType, sourcePort, targetPort)
 }
 
+// AddOutputDNAT delegates to the native firewall if available.
+func (m *Manager) AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	if m.nativeFirewall == nil {
+		return fmt.Errorf("output DNAT not supported without native firewall")
+	}
+	return m.nativeFirewall.AddOutputDNAT(localAddr, protocol, sourcePort, targetPort)
+}
+
+// RemoveOutputDNAT delegates to the native firewall if available.
+func (m *Manager) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error {
+	if m.nativeFirewall == nil {
+		return nil
+	}
+	return m.nativeFirewall.RemoveOutputDNAT(localAddr, protocol, sourcePort, targetPort)
+}
+
 // translateInboundPortDNAT applies port-specific DNAT translation to inbound packets.
 func (m *Manager) translateInboundPortDNAT(packetData []byte, d *decoder, srcIP, dstIP netip.Addr) bool {
 	if !m.portDNATEnabled.Load() {

client/firewall/uspfilter/rule.go

@@ -18,9 +18,7 @@ type PeerRule struct {
 	protoLayer gopacket.LayerType
 	sPort      *firewall.Port
 	dPort      *firewall.Port
-	drop       bool
-
-	udpHook func([]byte) bool
+	drop bool
 }
 
 // ID returns the rule id

client/firewall/uspfilter/tracer_test.go

@@ -399,21 +399,17 @@ func TestTracePacket(t *testing.T) {
 		{
 			name: "UDPTraffic_WithHook",
 			setup: func(m *Manager) {
-				hookFunc := func([]byte) bool {
-					return true
-				}
-				m.AddUDPPacketHook(true, netip.MustParseAddr("1.1.1.1"), 53, hookFunc)
+				m.SetUDPPacketHook(netip.MustParseAddr("100.10.255.254"), 53, func([]byte) bool {
+					return true // drop (intercepted by hook)
+				})
 			},
 			packetBuilder: func() *PacketBuilder {
-				return createPacketBuilder("1.1.1.1", "100.10.0.100", "udp", 12345, 53, fw.RuleDirectionIN)
+				return createPacketBuilder("100.10.0.100", "100.10.255.254", "udp", 12345, 53, fw.RuleDirectionOUT)
 			},
 			expectedStages: []PacketStage{
 				StageReceived,
-				StageInboundPortDNAT,
-				StageInbound1to1NAT,
-				StageConntrack,
-				StageRouting,
-				StagePeerACL,
+				StageOutbound1to1NAT,
+				StageOutboundPortReverse,
 				StageCompleted,
 			},
 			expectedAllow: false,

client/iface/bind/ice_bind_test.go

@@ -239,8 +239,12 @@ func TestICEBind_HandlesConcurrentMixedTraffic(t *testing.T) {
 		ipv6Count++
 	}
 
-	assert.Equal(t, packetsPerFamily, ipv4Count)
-	assert.Equal(t, packetsPerFamily, ipv6Count)
+	// Allow some UDP packet loss under load (e.g. FreeBSD/QEMU runners). The
+	// routing-correctness checks above are the real assertions; the counts
+	// are a sanity bound to catch a totally silent path.
+	minDelivered := packetsPerFamily * 80 / 100
+	assert.GreaterOrEqual(t, ipv4Count, minDelivered, "IPv4 delivery below threshold")
+	assert.GreaterOrEqual(t, ipv6Count, minDelivered, "IPv6 delivery below threshold")
 }
 
 func TestICEBind_DetectsAddressFamilyFromConnection(t *testing.T) {

client/iface/device/device_filter.go

@@ -3,6 +3,7 @@ package device
 import (
 	"net/netip"
 	"sync"
+	"sync/atomic"
 
 	"golang.zx2c4.com/wireguard/tun"
 )
@@ -15,14 +16,25 @@ type PacketFilter interface {
 	// FilterInbound filter incoming packets from external sources to host
 	FilterInbound(packetData []byte, size int) bool
 
-	// AddUDPPacketHook calls hook when UDP packet from given direction matched
-	//
-	// Hook function returns flag which indicates should be the matched package dropped or not.
-	// Hook function receives raw network packet data as argument.
-	AddUDPPacketHook(in bool, ip netip.Addr, dPort uint16, hook func(packet []byte) bool) string
+	// SetUDPPacketHook registers a hook for outbound UDP packets matching the given IP and port.
+	// Hook function returns true if the packet should be dropped.
+	// Only one UDP hook is supported; calling again replaces the previous hook.
+	// Pass nil hook to remove.
+	SetUDPPacketHook(ip netip.Addr, dPort uint16, hook func(packet []byte) bool)
 
-	// RemovePacketHook removes hook by ID
-	RemovePacketHook(hookID string) error
+	// SetTCPPacketHook registers a hook for outbound TCP packets matching the given IP and port.
+	// Hook function returns true if the packet should be dropped.
+	// Only one TCP hook is supported; calling again replaces the previous hook.
+	// Pass nil hook to remove.
+	SetTCPPacketHook(ip netip.Addr, dPort uint16, hook func(packet []byte) bool)
+}
+
+// PacketCapture captures raw packets for debugging. Implementations must be
+// safe for concurrent use and must not block.
+type PacketCapture interface {
+	// Offer submits a packet for capture. outbound is true for packets
+	// leaving the host (Read path), false for packets arriving (Write path).
+	Offer(data []byte, outbound bool)
 }
 
 // FilteredDevice to override Read or Write of packets
@@ -30,6 +42,7 @@ type FilteredDevice struct {
 	tun.Device
 
 	filter    PacketFilter
+	capture   atomic.Pointer[PacketCapture]
 	mutex     sync.RWMutex
 	closeOnce sync.Once
 }
@@ -60,20 +73,25 @@ func (d *FilteredDevice) Read(bufs [][]byte, sizes []int, offset int) (n int, er
 	if n, err = d.Device.Read(bufs, sizes, offset); err != nil {
 		return 0, err
 	}
+
 	d.mutex.RLock()
 	filter := d.filter
 	d.mutex.RUnlock()
 
-	if filter == nil {
-		return
+	if filter != nil {
+		for i := 0; i < n; i++ {
+			if filter.FilterOutbound(bufs[i][offset:offset+sizes[i]], sizes[i]) {
+				bufs = append(bufs[:i], bufs[i+1:]...)
+				sizes = append(sizes[:i], sizes[i+1:]...)
+				n--
+				i--
+			}
+		}
 	}
 
-	for i := 0; i < n; i++ {
-		if filter.FilterOutbound(bufs[i][offset:offset+sizes[i]], sizes[i]) {
-			bufs = append(bufs[:i], bufs[i+1:]...)
-			sizes = append(sizes[:i], sizes[i+1:]...)
-			n--
-			i--
+	if pc := d.capture.Load(); pc != nil {
+		for i := 0; i < n; i++ {
+			(*pc).Offer(bufs[i][offset:offset+sizes[i]], true)
 		}
 	}
 
@@ -82,6 +100,13 @@ func (d *FilteredDevice) Read(bufs [][]byte, sizes []int, offset int) (n int, er
 
 // Write wraps write method with filtering feature
 func (d *FilteredDevice) Write(bufs [][]byte, offset int) (int, error) {
+	// Capture before filtering so dropped packets are still visible in captures.
+	if pc := d.capture.Load(); pc != nil {
+		for _, buf := range bufs {
+			(*pc).Offer(buf[offset:], false)
+		}
+	}
+
 	d.mutex.RLock()
 	filter := d.filter
 	d.mutex.RUnlock()
@@ -93,9 +118,10 @@ func (d *FilteredDevice) Write(bufs [][]byte, offset int) (int, error) {
 	filteredBufs := make([][]byte, 0, len(bufs))
 	dropped := 0
 	for _, buf := range bufs {
-		if !filter.FilterInbound(buf[offset:], len(buf)) {
-			filteredBufs = append(filteredBufs, buf)
+		if filter.FilterInbound(buf[offset:], len(buf)) {
 			dropped++
+		} else {
+			filteredBufs = append(filteredBufs, buf)
 		}
 	}
 
@@ -110,3 +136,14 @@ func (d *FilteredDevice) SetFilter(filter PacketFilter) {
 	d.filter = filter
 	d.mutex.Unlock()
 }
+
+// SetCapture sets or clears the packet capture sink. Pass nil to disable.
+// Uses atomic store so the hot path (Read/Write) is a single pointer load
+// with no locking overhead when capture is off.
+func (d *FilteredDevice) SetCapture(pc PacketCapture) {
+	if pc == nil {
+		d.capture.Store(nil)
+		return
+	}
+	d.capture.Store(&pc)
+}

client/iface/device/device_filter_test.go

@@ -158,7 +158,7 @@ func TestDeviceWrapperRead(t *testing.T) {
 			t.Errorf("unexpected error: %v", err)
 			return
 		}
-		if n != 0 {
+		if n != 1 {
 			t.Errorf("expected n=1, got %d", n)
 			return
 		}

client/iface/iface.go

@@ -217,7 +217,6 @@ func (w *WGIface) RemoveAllowedIP(peerKey string, allowedIP netip.Prefix) error
 // Close closes the tunnel interface
 func (w *WGIface) Close() error {
 	w.mu.Lock()
-	defer w.mu.Unlock()
 
 	var result *multierror.Error
 
@@ -225,7 +224,15 @@ func (w *WGIface) Close() error {
 		result = multierror.Append(result, fmt.Errorf("failed to free WireGuard proxy: %w", err))
 	}
 
-	if err := w.tun.Close(); err != nil {
+	// Release w.mu before calling w.tun.Close(): the underlying
+	// wireguard-go device.Close() waits for its send/receive goroutines
+	// to drain. Some of those goroutines re-enter WGIface methods that
+	// take w.mu (e.g. the packet filter DNS hook calls GetDevice()), so
+	// holding the mutex here would deadlock the shutdown path.
+	tun := w.tun
+	w.mu.Unlock()
+
+	if err := tun.Close(); err != nil {
 		result = multierror.Append(result, fmt.Errorf("failed to close wireguard interface %s: %w", w.Name(), err))
 	}
 

client/iface/iface_close_test.go

@@ -0,0 +1,113 @@
+//go:build !android
+
+package iface
+
+import (
+	"errors"
+	"sync"
+	"testing"
+	"time"
+
+	wgdevice "golang.zx2c4.com/wireguard/device"
+	"golang.zx2c4.com/wireguard/tun/netstack"
+
+	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/udpmux"
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
+	"github.com/netbirdio/netbird/client/iface/wgproxy"
+)
+
+// fakeTunDevice implements WGTunDevice and lets the test control when
+// Close() returns. It mimics the wireguard-go shutdown path, which blocks
+// until its goroutines drain. Some of those goroutines (e.g. the packet
+// filter DNS hook in client/internal/dns) call back into WGIface, so if
+// WGIface.Close() held w.mu across tun.Close() the shutdown would
+// deadlock.
+type fakeTunDevice struct {
+	closeStarted chan struct{}
+	unblockClose chan struct{}
+}
+
+func (f *fakeTunDevice) Create() (device.WGConfigurer, error) {
+	return nil, errors.New("not implemented")
+}
+func (f *fakeTunDevice) Up() (*udpmux.UniversalUDPMuxDefault, error) {
+	return nil, errors.New("not implemented")
+}
+func (f *fakeTunDevice) UpdateAddr(wgaddr.Address) error      { return nil }
+func (f *fakeTunDevice) WgAddress() wgaddr.Address            { return wgaddr.Address{} }
+func (f *fakeTunDevice) MTU() uint16                          { return DefaultMTU }
+func (f *fakeTunDevice) DeviceName() string                   { return "nb-close-test" }
+func (f *fakeTunDevice) FilteredDevice() *device.FilteredDevice { return nil }
+func (f *fakeTunDevice) Device() *wgdevice.Device             { return nil }
+func (f *fakeTunDevice) GetNet() *netstack.Net                { return nil }
+func (f *fakeTunDevice) GetICEBind() device.EndpointManager   { return nil }
+
+func (f *fakeTunDevice) Close() error {
+	close(f.closeStarted)
+	<-f.unblockClose
+	return nil
+}
+
+type fakeProxyFactory struct{}
+
+func (fakeProxyFactory) GetProxy() wgproxy.Proxy { return nil }
+func (fakeProxyFactory) GetProxyPort() uint16    { return 0 }
+func (fakeProxyFactory) Free() error             { return nil }
+
+// TestWGIface_CloseReleasesMutexBeforeTunClose guards against a deadlock
+// that surfaces as a macOS test-timeout in
+// TestDNSPermanent_updateUpstream: WGIface.Close() used to hold w.mu
+// while waiting for the wireguard-go device goroutines to finish, and
+// one of those goroutines (the DNS filter hook) calls back into
+// WGIface.GetDevice() which needs the same mutex. The fix is to drop
+// the lock before tun.Close() returns control.
+func TestWGIface_CloseReleasesMutexBeforeTunClose(t *testing.T) {
+	tun := &fakeTunDevice{
+		closeStarted: make(chan struct{}),
+		unblockClose: make(chan struct{}),
+	}
+	w := &WGIface{
+		tun:            tun,
+		wgProxyFactory: fakeProxyFactory{},
+	}
+
+	closeDone := make(chan error, 1)
+	go func() {
+		closeDone <- w.Close()
+	}()
+
+	select {
+	case <-tun.closeStarted:
+	case <-time.After(2 * time.Second):
+		close(tun.unblockClose)
+		t.Fatal("tun.Close() was never invoked")
+	}
+
+	// Simulate the WireGuard read goroutine calling back into WGIface
+	// via the packet filter's DNS hook. If Close() still held w.mu
+	// during tun.Close(), this would block until the test timeout.
+	getDeviceDone := make(chan struct{})
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		_ = w.GetDevice()
+		close(getDeviceDone)
+	}()
+
+	select {
+	case <-getDeviceDone:
+	case <-time.After(2 * time.Second):
+		close(tun.unblockClose)
+		wg.Wait()
+		t.Fatal("GetDevice() deadlocked while WGIface.Close was closing the tun")
+	}
+
+	close(tun.unblockClose)
+	select {
+	case <-closeDone:
+	case <-time.After(2 * time.Second):
+		t.Fatal("WGIface.Close() never returned after the tun was unblocked")
+	}
+}

client/iface/mocks/filter.go

@@ -34,18 +34,28 @@ func (m *MockPacketFilter) EXPECT() *MockPacketFilterMockRecorder {
 	return m.recorder
 }
 
-// AddUDPPacketHook mocks base method.
-func (m *MockPacketFilter) AddUDPPacketHook(arg0 bool, arg1 netip.Addr, arg2 uint16, arg3 func([]byte) bool) string {
+// SetUDPPacketHook mocks base method.
+func (m *MockPacketFilter) SetUDPPacketHook(arg0 netip.Addr, arg1 uint16, arg2 func([]byte) bool) {
 	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "AddUDPPacketHook", arg0, arg1, arg2, arg3)
-	ret0, _ := ret[0].(string)
-	return ret0
+	m.ctrl.Call(m, "SetUDPPacketHook", arg0, arg1, arg2)
 }
 
-// AddUDPPacketHook indicates an expected call of AddUDPPacketHook.
-func (mr *MockPacketFilterMockRecorder) AddUDPPacketHook(arg0, arg1, arg2, arg3 interface{}) *gomock.Call {
+// SetUDPPacketHook indicates an expected call of SetUDPPacketHook.
+func (mr *MockPacketFilterMockRecorder) SetUDPPacketHook(arg0, arg1, arg2 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "AddUDPPacketHook", reflect.TypeOf((*MockPacketFilter)(nil).AddUDPPacketHook), arg0, arg1, arg2, arg3)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SetUDPPacketHook", reflect.TypeOf((*MockPacketFilter)(nil).SetUDPPacketHook), arg0, arg1, arg2)
+}
+
+// SetTCPPacketHook mocks base method.
+func (m *MockPacketFilter) SetTCPPacketHook(arg0 netip.Addr, arg1 uint16, arg2 func([]byte) bool) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "SetTCPPacketHook", arg0, arg1, arg2)
+}
+
+// SetTCPPacketHook indicates an expected call of SetTCPPacketHook.
+func (mr *MockPacketFilterMockRecorder) SetTCPPacketHook(arg0, arg1, arg2 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SetTCPPacketHook", reflect.TypeOf((*MockPacketFilter)(nil).SetTCPPacketHook), arg0, arg1, arg2)
 }
 
 // FilterInbound mocks base method.
@@ -75,17 +85,3 @@ func (mr *MockPacketFilterMockRecorder) FilterOutbound(arg0 interface{}, arg1 an
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "FilterOutbound", reflect.TypeOf((*MockPacketFilter)(nil).FilterOutbound), arg0, arg1)
 }
-
-// RemovePacketHook mocks base method.
-func (m *MockPacketFilter) RemovePacketHook(arg0 string) error {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "RemovePacketHook", arg0)
-	ret0, _ := ret[0].(error)
-	return ret0
-}
-
-// RemovePacketHook indicates an expected call of RemovePacketHook.
-func (mr *MockPacketFilterMockRecorder) RemovePacketHook(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "RemovePacketHook", reflect.TypeOf((*MockPacketFilter)(nil).RemovePacketHook), arg0)
-}

client/iface/mocks/iface/mocks/filter.go

@@ -1,87 +0,0 @@
-// Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/netbirdio/netbird/client/iface (interfaces: PacketFilter)
-
-// Package mocks is a generated GoMock package.
-package mocks
-
-import (
-	net "net"
-	reflect "reflect"
-
-	gomock "github.com/golang/mock/gomock"
-)
-
-// MockPacketFilter is a mock of PacketFilter interface.
-type MockPacketFilter struct {
-	ctrl     *gomock.Controller
-	recorder *MockPacketFilterMockRecorder
-}
-
-// MockPacketFilterMockRecorder is the mock recorder for MockPacketFilter.
-type MockPacketFilterMockRecorder struct {
-	mock *MockPacketFilter
-}
-
-// NewMockPacketFilter creates a new mock instance.
-func NewMockPacketFilter(ctrl *gomock.Controller) *MockPacketFilter {
-	mock := &MockPacketFilter{ctrl: ctrl}
-	mock.recorder = &MockPacketFilterMockRecorder{mock}
-	return mock
-}
-
-// EXPECT returns an object that allows the caller to indicate expected use.
-func (m *MockPacketFilter) EXPECT() *MockPacketFilterMockRecorder {
-	return m.recorder
-}
-
-// AddUDPPacketHook mocks base method.
-func (m *MockPacketFilter) AddUDPPacketHook(arg0 bool, arg1 net.IP, arg2 uint16, arg3 func(*net.UDPAddr, []byte) bool) {
-	m.ctrl.T.Helper()
-	m.ctrl.Call(m, "AddUDPPacketHook", arg0, arg1, arg2, arg3)
-}
-
-// AddUDPPacketHook indicates an expected call of AddUDPPacketHook.
-func (mr *MockPacketFilterMockRecorder) AddUDPPacketHook(arg0, arg1, arg2, arg3 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "AddUDPPacketHook", reflect.TypeOf((*MockPacketFilter)(nil).AddUDPPacketHook), arg0, arg1, arg2, arg3)
-}
-
-// FilterInbound mocks base method.
-func (m *MockPacketFilter) FilterInbound(arg0 []byte) bool {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "FilterInbound", arg0)
-	ret0, _ := ret[0].(bool)
-	return ret0
-}
-
-// FilterInbound indicates an expected call of FilterInbound.
-func (mr *MockPacketFilterMockRecorder) FilterInbound(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "FilterInbound", reflect.TypeOf((*MockPacketFilter)(nil).FilterInbound), arg0)
-}
-
-// FilterOutbound mocks base method.
-func (m *MockPacketFilter) FilterOutbound(arg0 []byte) bool {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "FilterOutbound", arg0)
-	ret0, _ := ret[0].(bool)
-	return ret0
-}
-
-// FilterOutbound indicates an expected call of FilterOutbound.
-func (mr *MockPacketFilterMockRecorder) FilterOutbound(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "FilterOutbound", reflect.TypeOf((*MockPacketFilter)(nil).FilterOutbound), arg0)
-}
-
-// SetNetwork mocks base method.
-func (m *MockPacketFilter) SetNetwork(arg0 *net.IPNet) {
-	m.ctrl.T.Helper()
-	m.ctrl.Call(m, "SetNetwork", arg0)
-}
-
-// SetNetwork indicates an expected call of SetNetwork.
-func (mr *MockPacketFilterMockRecorder) SetNetwork(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SetNetwork", reflect.TypeOf((*MockPacketFilter)(nil).SetNetwork), arg0)
-}

client/iface/udpmux/universal.go

@@ -171,7 +171,7 @@ func (u *UDPConn) performFilterCheck(addr net.Addr) error {
 	}
 
 	if u.address.Network.Contains(a) {
-		log.Warnf("Address %s is part of the NetBird network %s, refusing to write", addr, u.address)
+		log.Warnf("address %s is part of the NetBird network %s, refusing to write", addr, u.address)
 		return fmt.Errorf("address %s is part of the NetBird network %s, refusing to write", addr, u.address)
 	}
 
@@ -181,7 +181,7 @@ func (u *UDPConn) performFilterCheck(addr net.Addr) error {
 		u.addrCache.Store(addr.String(), isRouted)
 		if isRouted {
 			// Extra log, as the error only shows up with ICE logging enabled
-			log.Infof("Address %s is part of routed network %s, refusing to write", addr, prefix)
+			log.Infof("address %s is part of routed network %s, refusing to write", addr, prefix)
 			return fmt.Errorf("address %s is part of routed network %s, refusing to write", addr, prefix)
 		}
 	}

client/installer.nsis

@@ -201,7 +201,18 @@ Pop $0
 
 Function .onInit
 StrCpy $INSTDIR "${INSTALL_DIR}"
+; Default autostart to enabled so silent installs (/S) match the interactive default
+StrCpy $AutostartEnabled "1"
+
+; Pre-0.70.1 installers ran without SetRegView, so their uninstall keys live
+; in the 32-bit view. Fall back to it so upgrades still find them.
+SetRegView 64
 ReadRegStr $R0 HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\$(^NAME)" "UninstallString"
+${If} $R0 == ""
+    SetRegView 32
+    ReadRegStr $R0 HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\$(^NAME)" "UninstallString"
+    SetRegView 64
+${EndIf}
 ${If} $R0 != ""
     # if silent install jump to uninstall step
     IfSilent uninstall
@@ -214,6 +225,10 @@ ${If} $R0 != ""
 
 ${EndIf}
 FunctionEnd
+
+Function un.onInit
+SetRegView 64
+FunctionEnd
 ######################################################################
 Section -MainProgram
     ${INSTALL_TYPE}
@@ -228,6 +243,7 @@ Section -MainProgram
     !else
         File /r "..\\dist\\netbird_windows_amd64\\"
     !endif
+    File "..\\client\\ui\\assets\\netbird.png"
 SectionEnd
 ######################################################################
 
@@ -247,9 +263,11 @@ WriteRegStr ${REG_ROOT} "${UI_REG_APP_PATH}" "" "$INSTDIR\${UI_APP_EXE}"
 ; Create autostart registry entry based on checkbox
 DetailPrint "Autostart enabled: $AutostartEnabled"
 ${If} $AutostartEnabled == "1"
-    WriteRegStr HKCU "${AUTOSTART_REG_KEY}" "${APP_NAME}" "$INSTDIR\${UI_APP_EXE}.exe"
+    WriteRegStr HKLM "${AUTOSTART_REG_KEY}" "${APP_NAME}" '"$INSTDIR\${UI_APP_EXE}.exe"'
     DetailPrint "Added autostart registry entry: $INSTDIR\${UI_APP_EXE}.exe"
 ${Else}
+    DeleteRegValue HKLM "${AUTOSTART_REG_KEY}" "${APP_NAME}"
+    ; Legacy: pre-HKLM installs wrote to HKCU; clean that up too.
     DeleteRegValue HKCU "${AUTOSTART_REG_KEY}" "${APP_NAME}"
     DetailPrint "Autostart not enabled by user"
 ${EndIf}
@@ -283,6 +301,8 @@ ExecWait `taskkill /im ${UI_APP_EXE}.exe /f`
 
 ; Remove autostart registry entry
 DetailPrint "Removing autostart registry entry if exists..."
+DeleteRegValue HKLM "${AUTOSTART_REG_KEY}" "${APP_NAME}"
+; Legacy: pre-HKLM installs wrote to HKCU; clean that up too.
 DeleteRegValue HKCU "${AUTOSTART_REG_KEY}" "${APP_NAME}"
 
 ; Handle data deletion based on checkbox
@@ -321,6 +341,7 @@ DetailPrint "Removing registry keys..."
 DeleteRegKey ${REG_ROOT} "${REG_APP_PATH}"
 DeleteRegKey ${REG_ROOT} "${UNINSTALL_PATH}"
 DeleteRegKey ${REG_ROOT} "${UI_REG_APP_PATH}"
+DeleteRegKey HKCU "Software\Classes\AppUserModelId\${APP_NAME}"
 
 DetailPrint "Removing application directory from PATH..."
 EnVar::SetHKLM

client/internal/acl/manager_test.go

@@ -19,6 +19,9 @@ import (
 var flowLogger = netflow.NewManager(nil, []byte{}, nil).GetLogger()
 
 func TestDefaultManager(t *testing.T) {
+	t.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	t.Setenv(firewall.EnvForceUserspaceFirewall, "true")
+
 	networkMap := &mgmProto.NetworkMap{
 		FirewallRules: []*mgmProto.FirewallRule{
 			{
@@ -135,6 +138,7 @@ func TestDefaultManager(t *testing.T) {
 func TestDefaultManagerStateless(t *testing.T) {
 	// stateless currently only in userspace, so we have to disable kernel
 	t.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	t.Setenv(firewall.EnvForceUserspaceFirewall, "true")
 	t.Setenv("NB_DISABLE_CONNTRACK", "true")
 
 	networkMap := &mgmProto.NetworkMap{
@@ -194,6 +198,7 @@ func TestDefaultManagerStateless(t *testing.T) {
 // This tests the full ACL manager -> uspfilter integration.
 func TestDenyRulesNotAccumulatedOnRepeatedApply(t *testing.T) {
 	t.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	t.Setenv(firewall.EnvForceUserspaceFirewall, "true")
 
 	networkMap := &mgmProto.NetworkMap{
 		FirewallRules: []*mgmProto.FirewallRule{
@@ -258,6 +263,7 @@ func TestDenyRulesNotAccumulatedOnRepeatedApply(t *testing.T) {
 // up when they're removed from the network map in a subsequent update.
 func TestDenyRulesCleanedUpOnRemoval(t *testing.T) {
 	t.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	t.Setenv(firewall.EnvForceUserspaceFirewall, "true")
 
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
@@ -339,6 +345,7 @@ func TestDenyRulesCleanedUpOnRemoval(t *testing.T) {
 // one added without leaking.
 func TestRuleUpdateChangingAction(t *testing.T) {
 	t.Setenv("NB_WG_KERNEL_DISABLED", "true")
+	t.Setenv(firewall.EnvForceUserspaceFirewall, "true")
 
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()

client/internal/auth/auth.go

@@ -155,7 +155,7 @@ func (a *Auth) IsLoginRequired(ctx context.Context) (bool, error) {
 	var needsLogin bool
 
 	err = a.withRetry(ctx, func(client *mgm.GrpcClient) error {
-		_, _, err := a.doMgmLogin(client, ctx, pubSSHKey)
+		err := a.doMgmLogin(client, ctx, pubSSHKey)
 		if isLoginNeeded(err) {
 			needsLogin = true
 			return nil
@@ -179,8 +179,8 @@ func (a *Auth) Login(ctx context.Context, setupKey string, jwtToken string) (err
 	var isAuthError bool
 
 	err = a.withRetry(ctx, func(client *mgm.GrpcClient) error {
-		serverKey, _, err := a.doMgmLogin(client, ctx, pubSSHKey)
-		if serverKey != nil && isRegistrationNeeded(err) {
+		err := a.doMgmLogin(client, ctx, pubSSHKey)
+		if isRegistrationNeeded(err) {
 			log.Debugf("peer registration required")
 			_, err = a.registerPeer(client, ctx, setupKey, jwtToken, pubSSHKey)
 			if err != nil {
@@ -201,13 +201,7 @@ func (a *Auth) Login(ctx context.Context, setupKey string, jwtToken string) (err
 
 // getPKCEFlow retrieves PKCE authorization flow configuration and creates a flow instance
 func (a *Auth) getPKCEFlow(client *mgm.GrpcClient) (*PKCEAuthorizationFlow, error) {
-	serverKey, err := client.GetServerPublicKey()
-	if err != nil {
-		log.Errorf("failed while getting Management Service public key: %v", err)
-		return nil, err
-	}
-
-	protoFlow, err := client.GetPKCEAuthorizationFlow(*serverKey)
+	protoFlow, err := client.GetPKCEAuthorizationFlow()
 	if err != nil {
 		if s, ok := status.FromError(err); ok && s.Code() == codes.NotFound {
 			log.Warnf("server couldn't find pkce flow, contact admin: %v", err)
@@ -246,13 +240,7 @@ func (a *Auth) getPKCEFlow(client *mgm.GrpcClient) (*PKCEAuthorizationFlow, erro
 
 // getDeviceFlow retrieves device authorization flow configuration and creates a flow instance
 func (a *Auth) getDeviceFlow(client *mgm.GrpcClient) (*DeviceAuthorizationFlow, error) {
-	serverKey, err := client.GetServerPublicKey()
-	if err != nil {
-		log.Errorf("failed while getting Management Service public key: %v", err)
-		return nil, err
-	}
-
-	protoFlow, err := client.GetDeviceAuthorizationFlow(*serverKey)
+	protoFlow, err := client.GetDeviceAuthorizationFlow()
 	if err != nil {
 		if s, ok := status.FromError(err); ok && s.Code() == codes.NotFound {
 			log.Warnf("server couldn't find device flow, contact admin: %v", err)
@@ -292,28 +280,16 @@ func (a *Auth) getDeviceFlow(client *mgm.GrpcClient) (*DeviceAuthorizationFlow,
 }
 
 // doMgmLogin performs the actual login operation with the management service
-func (a *Auth) doMgmLogin(client *mgm.GrpcClient, ctx context.Context, pubSSHKey []byte) (*wgtypes.Key, *mgmProto.LoginResponse, error) {
-	serverKey, err := client.GetServerPublicKey()
-	if err != nil {
-		log.Errorf("failed while getting Management Service public key: %v", err)
-		return nil, nil, err
-	}
-
+func (a *Auth) doMgmLogin(client *mgm.GrpcClient, ctx context.Context, pubSSHKey []byte) error {
 	sysInfo := system.GetInfo(ctx)
 	a.setSystemInfoFlags(sysInfo)
-	loginResp, err := client.Login(*serverKey, sysInfo, pubSSHKey, a.config.DNSLabels)
-	return serverKey, loginResp, err
+	_, err := client.Login(sysInfo, pubSSHKey, a.config.DNSLabels)
+	return err
 }
 
 // registerPeer checks whether setupKey was provided via cmd line and if not then it prompts user to enter a key.
 // Otherwise tries to register with the provided setupKey via command line.
 func (a *Auth) registerPeer(client *mgm.GrpcClient, ctx context.Context, setupKey string, jwtToken string, pubSSHKey []byte) (*mgmProto.LoginResponse, error) {
-	serverPublicKey, err := client.GetServerPublicKey()
-	if err != nil {
-		log.Errorf("failed while getting Management Service public key: %v", err)
-		return nil, err
-	}
-
 	validSetupKey, err := uuid.Parse(setupKey)
 	if err != nil && jwtToken == "" {
 		return nil, status.Errorf(codes.InvalidArgument, "invalid setup-key or no sso information provided, err: %v", err)
@@ -322,7 +298,7 @@ func (a *Auth) registerPeer(client *mgm.GrpcClient, ctx context.Context, setupKe
 	log.Debugf("sending peer registration request to Management Service")
 	info := system.GetInfo(ctx)
 	a.setSystemInfoFlags(info)
-	loginResp, err := client.Register(*serverPublicKey, validSetupKey.String(), jwtToken, info, pubSSHKey, a.config.DNSLabels)
+	loginResp, err := client.Register(validSetupKey.String(), jwtToken, info, pubSSHKey, a.config.DNSLabels)
 	if err != nil {
 		log.Errorf("failed registering peer %v", err)
 		return nil, err

client/internal/connect.go

@@ -94,6 +94,7 @@ func (c *ConnectClient) RunOnAndroid(
 	dnsAddresses []netip.AddrPort,
 	dnsReadyListener dns.ReadyListener,
 	stateFilePath string,
+	cacheDir string,
 ) error {
 	// in case of non Android os these variables will be nil
 	mobileDependency := MobileDependency{
@@ -103,6 +104,7 @@ func (c *ConnectClient) RunOnAndroid(
 		HostDNSAddresses:      dnsAddresses,
 		DnsReadyListener:      dnsReadyListener,
 		StateFilePath:         stateFilePath,
+		TempDir:               cacheDir,
 	}
 	return c.run(mobileDependency, nil, "")
 }
@@ -111,6 +113,7 @@ func (c *ConnectClient) RunOniOS(
 	fileDescriptor int32,
 	networkChangeListener listener.NetworkChangeListener,
 	dnsManager dns.IosDnsManager,
+	dnsAddresses []netip.AddrPort,
 	stateFilePath string,
 ) error {
 	// Set GC percent to 5% to reduce memory usage as iOS only allows 50MB of memory for the extension.
@@ -120,6 +123,7 @@ func (c *ConnectClient) RunOniOS(
 		FileDescriptor:        fileDescriptor,
 		NetworkChangeListener: networkChangeListener,
 		DnsManager:            dnsManager,
+		HostDNSAddresses:      dnsAddresses,
 		StateFilePath:         stateFilePath,
 	}
 	return c.run(mobileDependency, nil, "")
@@ -329,6 +333,10 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 		c.statusRecorder.MarkSignalConnected()
 
 		relayURLs, token := parseRelayInfo(loginResp)
+		if override, ok := peer.OverrideRelayURLs(); ok {
+			log.Infof("overriding relay URLs from %s: %v", peer.EnvKeyNBHomeRelayServers, override)
+			relayURLs = override
+		}
 		peerConfig := loginResp.GetPeerConfig()
 
 		engineConfig, err := createEngineConfig(myPrivateKey, c.config, peerConfig, logPath)
@@ -336,6 +344,7 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 			log.Error(err)
 			return wrapErr(err)
 		}
+		engineConfig.TempDir = mobileDependency.TempDir
 
 		relayManager := relayClient.NewManager(engineCtx, relayURLs, myPrivateKey.PublicKey().String(), engineConfig.MTU)
 		c.statusRecorder.SetRelayMgr(relayManager)
@@ -617,12 +626,6 @@ func connectToSignal(ctx context.Context, wtConfig *mgmProto.NetbirdConfig, ourP
 
 // loginToManagement creates Management ServiceDependencies client, establishes a connection, logs-in and gets a global Netbird config (signal, turn, stun hosts, etc)
 func loginToManagement(ctx context.Context, client mgm.Client, pubSSHKey []byte, config *profilemanager.Config) (*mgmProto.LoginResponse, error) {
-
-	serverPublicKey, err := client.GetServerPublicKey()
-	if err != nil {
-		return nil, gstatus.Errorf(codes.FailedPrecondition, "failed while getting Management Service public key: %s", err)
-	}
-
 	sysInfo := system.GetInfo(ctx)
 	sysInfo.SetFlags(
 		config.RosenpassEnabled,
@@ -641,12 +644,7 @@ func loginToManagement(ctx context.Context, client mgm.Client, pubSSHKey []byte,
 		config.EnableSSHRemotePortForwarding,
 		config.DisableSSHAuth,
 	)
-	loginResp, err := client.Login(*serverPublicKey, sysInfo, pubSSHKey, config.DNSLabels)
-	if err != nil {
-		return nil, err
-	}
-
-	return loginResp, nil
+	return client.Login(sysInfo, pubSSHKey, config.DNSLabels)
 }
 
 func statusRecorderToMgmConnStateNotifier(statusRecorder *peer.Status) mgm.ConnStateNotifier {

client/internal/debug/debug.go

@@ -16,7 +16,6 @@ import (
 	"path/filepath"
 	"runtime"
 	"runtime/pprof"
-	"slices"
 	"sort"
 	"strings"
 	"time"
@@ -25,12 +24,12 @@ import (
 	"google.golang.org/protobuf/encoding/protojson"
 
 	"github.com/netbirdio/netbird/client/anonymize"
+	"github.com/netbirdio/netbird/client/configs"
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/internal/profilemanager"
 	"github.com/netbirdio/netbird/client/internal/updater/installer"
 	nbstatus "github.com/netbirdio/netbird/client/status"
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
-	"github.com/netbirdio/netbird/util"
 )
 
 const readmeContent = `Netbird debug bundle
@@ -52,6 +51,7 @@ resolved_domains.txt: Anonymized resolved domain IP addresses from the status re
 config.txt: Anonymized configuration information of the NetBird client.
 network_map.json: Anonymized sync response containing peer configurations, routes, DNS settings, and firewall rules.
 state.json: Anonymized client state dump containing netbird states for the active profile.
+service_params.json: Sanitized service install parameters (service.json). Sensitive environment variable values are masked. Only present when service.json exists.
 metrics.txt: Buffered client metrics in InfluxDB line protocol format. Only present when metrics collection is enabled. Peer identifiers are anonymized.
 mutex.prof: Mutex profiling information.
 goroutine.prof: Goroutine profiling information.
@@ -61,6 +61,7 @@ allocs.prof: Allocations profiling information.
 threadcreate.prof: Thread creation profiling information.
 cpu.prof: CPU profiling information.
 stack_trace.txt: Complete stack traces of all goroutines at the time of bundle creation.
+capture.pcap: Packet capture in pcap format. Only present when capture was running during bundle collection. Omitted from anonymized bundles because it contains raw decrypted packet data.
 
 
 Anonymization Process
@@ -232,7 +233,9 @@ type BundleGenerator struct {
 	statusRecorder *peer.Status
 	syncResponse   *mgmProto.SyncResponse
 	logPath        string
+	tempDir        string
 	cpuProfile     []byte
+	capturePath    string
 	refreshStatus  func() // Optional callback to refresh status before bundle generation
 	clientMetrics  MetricsExporter
 
@@ -254,8 +257,10 @@ type GeneratorDependencies struct {
 	StatusRecorder *peer.Status
 	SyncResponse   *mgmProto.SyncResponse
 	LogPath        string
+	TempDir        string // Directory for temporary bundle zip files. If empty, os.TempDir() is used.
 	CPUProfile     []byte
-	RefreshStatus  func() // Optional callback to refresh status before bundle generation
+	CapturePath    string
+	RefreshStatus  func()
 	ClientMetrics  MetricsExporter
 }
 
@@ -273,7 +278,9 @@ func NewBundleGenerator(deps GeneratorDependencies, cfg BundleConfig) *BundleGen
 		statusRecorder: deps.StatusRecorder,
 		syncResponse:   deps.SyncResponse,
 		logPath:        deps.LogPath,
+		tempDir:        deps.TempDir,
 		cpuProfile:     deps.CPUProfile,
+		capturePath:    deps.CapturePath,
 		refreshStatus:  deps.RefreshStatus,
 		clientMetrics:  deps.ClientMetrics,
 
@@ -285,7 +292,7 @@ func NewBundleGenerator(deps GeneratorDependencies, cfg BundleConfig) *BundleGen
 
 // Generate creates a debug bundle and returns the location.
 func (g *BundleGenerator) Generate() (resp string, err error) {
-	bundlePath, err := os.CreateTemp("", "netbird.debug.*.zip")
+	bundlePath, err := os.CreateTemp(g.tempDir, "netbird.debug.*.zip")
 	if err != nil {
 		return "", fmt.Errorf("create zip file: %w", err)
 	}
@@ -343,6 +350,10 @@ func (g *BundleGenerator) createArchive() error {
 		log.Errorf("failed to add CPU profile to debug bundle: %v", err)
 	}
 
+	if err := g.addCaptureFile(); err != nil {
+		log.Errorf("failed to add capture file to debug bundle: %v", err)
+	}
+
 	if err := g.addStackTrace(); err != nil {
 		log.Errorf("failed to add stack trace to debug bundle: %v", err)
 	}
@@ -359,6 +370,10 @@ func (g *BundleGenerator) createArchive() error {
 		log.Errorf("failed to add corrupted state files to debug bundle: %v", err)
 	}
 
+	if err := g.addServiceParams(); err != nil {
+		log.Errorf("failed to add service params to debug bundle: %v", err)
+	}
+
 	if err := g.addMetrics(); err != nil {
 		log.Errorf("failed to add metrics to debug bundle: %v", err)
 	}
@@ -367,15 +382,8 @@ func (g *BundleGenerator) createArchive() error {
 		log.Errorf("failed to add wg show output: %v", err)
 	}
 
-	if g.logPath != "" && !slices.Contains(util.SpecialLogs, g.logPath) {
-		if err := g.addLogfile(); err != nil {
-			log.Errorf("failed to add log file to debug bundle: %v", err)
-			if err := g.trySystemdLogFallback(); err != nil {
-				log.Errorf("failed to add systemd logs as fallback: %v", err)
-			}
-		}
-	} else if err := g.trySystemdLogFallback(); err != nil {
-		log.Errorf("failed to add systemd logs: %v", err)
+	if err := g.addPlatformLog(); err != nil {
+		log.Errorf("failed to add logs to debug bundle: %v", err)
 	}
 
 	if err := g.addUpdateLogs(); err != nil {
@@ -488,6 +496,90 @@ func (g *BundleGenerator) addConfig() error {
 	return nil
 }
 
+const (
+	serviceParamsFile    = "service.json"
+	serviceParamsBundle  = "service_params.json"
+	maskedValue          = "***"
+	envVarPrefix         = "NB_"
+	jsonKeyManagementURL = "management_url"
+	jsonKeyServiceEnv    = "service_env_vars"
+)
+
+var sensitiveEnvSubstrings = []string{"key", "token", "secret", "password", "credential"}
+
+// addServiceParams reads the service.json file and adds a sanitized version to the bundle.
+// Non-NB_ env vars and vars with sensitive names are masked. Other NB_ values are anonymized.
+func (g *BundleGenerator) addServiceParams() error {
+	path := filepath.Join(configs.StateDir, serviceParamsFile)
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return fmt.Errorf("read service params: %w", err)
+	}
+
+	var params map[string]any
+	if err := json.Unmarshal(data, &params); err != nil {
+		return fmt.Errorf("parse service params: %w", err)
+	}
+
+	if g.anonymize {
+		if mgmtURL, ok := params[jsonKeyManagementURL].(string); ok && mgmtURL != "" {
+			params[jsonKeyManagementURL] = g.anonymizer.AnonymizeURI(mgmtURL)
+		}
+	}
+
+	g.sanitizeServiceEnvVars(params)
+
+	sanitizedData, err := json.MarshalIndent(params, "", "  ")
+	if err != nil {
+		return fmt.Errorf("marshal sanitized service params: %w", err)
+	}
+
+	if err := g.addFileToZip(bytes.NewReader(sanitizedData), serviceParamsBundle); err != nil {
+		return fmt.Errorf("add service params to zip: %w", err)
+	}
+
+	return nil
+}
+
+// sanitizeServiceEnvVars masks or anonymizes env var values in service params.
+// Non-NB_ vars and vars with sensitive names (key, token, etc.) are fully masked.
+// Other NB_ var values are passed through the anonymizer when anonymization is enabled.
+func (g *BundleGenerator) sanitizeServiceEnvVars(params map[string]any) {
+	envVars, ok := params[jsonKeyServiceEnv].(map[string]any)
+	if !ok {
+		return
+	}
+
+	sanitized := make(map[string]any, len(envVars))
+	for k, v := range envVars {
+		val, _ := v.(string)
+		switch {
+		case !strings.HasPrefix(k, envVarPrefix) || isSensitiveEnvVar(k):
+			sanitized[k] = maskedValue
+		case g.anonymize:
+			sanitized[k] = g.anonymizer.AnonymizeString(val)
+		default:
+			sanitized[k] = val
+		}
+	}
+	params[jsonKeyServiceEnv] = sanitized
+}
+
+// isSensitiveEnvVar returns true for env var names that may contain secrets.
+func isSensitiveEnvVar(key string) bool {
+	lower := strings.ToLower(key)
+	for _, s := range sensitiveEnvSubstrings {
+		if strings.Contains(lower, s) {
+			return true
+		}
+	}
+	return false
+}
+
 func (g *BundleGenerator) addCommonConfigFields(configContent *strings.Builder) {
 	configContent.WriteString("NetBird Client Configuration:\n\n")
 
@@ -585,6 +677,29 @@ func (g *BundleGenerator) addCPUProfile() error {
 	return nil
 }
 
+func (g *BundleGenerator) addCaptureFile() error {
+	if g.capturePath == "" {
+		return nil
+	}
+
+	if g.anonymize {
+		log.Info("skipping capture file in anonymized bundle (contains raw packet data)")
+		return nil
+	}
+
+	f, err := os.Open(g.capturePath)
+	if err != nil {
+		return fmt.Errorf("open capture file: %w", err)
+	}
+	defer f.Close()
+
+	if err := g.addFileToZip(f, "capture.pcap"); err != nil {
+		return fmt.Errorf("add capture file to zip: %w", err)
+	}
+
+	return nil
+}
+
 func (g *BundleGenerator) addStackTrace() error {
 	buf := make([]byte, 5242880) // 5 MB buffer
 	n := runtime.Stack(buf, true)

client/internal/debug/debug_android.go

@@ -0,0 +1,41 @@
+//go:build android
+
+package debug
+
+import (
+	"fmt"
+	"io"
+	"os/exec"
+
+	log "github.com/sirupsen/logrus"
+)
+
+func (g *BundleGenerator) addPlatformLog() error {
+	cmd := exec.Command("/system/bin/logcat", "-d")
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("logcat stdout pipe: %w", err)
+	}
+
+	if err := cmd.Start(); err != nil {
+		return fmt.Errorf("start logcat: %w", err)
+	}
+
+	var logReader io.Reader = stdout
+	if g.anonymize {
+		var pw *io.PipeWriter
+		logReader, pw = io.Pipe()
+		go anonymizeLog(stdout, pw, g.anonymizer)
+	}
+
+	if err := g.addFileToZip(logReader, "logcat.txt"); err != nil {
+		return fmt.Errorf("add logcat to zip: %w", err)
+	}
+
+	if err := cmd.Wait(); err != nil {
+		return fmt.Errorf("wait logcat: %w", err)
+	}
+
+	log.Debug("added logcat output to debug bundle")
+	return nil
+}

client/internal/debug/debug_nonandroid.go

@@ -0,0 +1,25 @@
+//go:build !android
+
+package debug
+
+import (
+	"slices"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/util"
+)
+
+func (g *BundleGenerator) addPlatformLog() error {
+	if g.logPath != "" && !slices.Contains(util.SpecialLogs, g.logPath) {
+		if err := g.addLogfile(); err != nil {
+			log.Errorf("failed to add log file to debug bundle: %v", err)
+			if err := g.trySystemdLogFallback(); err != nil {
+				return err
+			}
+		}
+	} else if err := g.trySystemdLogFallback(); err != nil {
+		return err
+	}
+	return nil
+}

client/internal/debug/debug_test.go

@@ -1,8 +1,12 @@
 package debug
 
 import (
+	"archive/zip"
+	"bytes"
 	"encoding/json"
 	"net"
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 
@@ -10,6 +14,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/netbirdio/netbird/client/anonymize"
+	"github.com/netbirdio/netbird/client/configs"
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
 )
 
@@ -420,6 +425,226 @@ func TestAnonymizeNetworkMap(t *testing.T) {
 	}
 }
 
+func TestIsSensitiveEnvVar(t *testing.T) {
+	tests := []struct {
+		key       string
+		sensitive bool
+	}{
+		{"NB_SETUP_KEY", true},
+		{"NB_API_TOKEN", true},
+		{"NB_CLIENT_SECRET", true},
+		{"NB_PASSWORD", true},
+		{"NB_CREDENTIAL", true},
+		{"NB_LOG_LEVEL", false},
+		{"NB_MANAGEMENT_URL", false},
+		{"NB_HOSTNAME", false},
+		{"HOME", false},
+		{"PATH", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.key, func(t *testing.T) {
+			assert.Equal(t, tt.sensitive, isSensitiveEnvVar(tt.key))
+		})
+	}
+}
+
+func TestSanitizeServiceEnvVars(t *testing.T) {
+	tests := []struct {
+		name      string
+		anonymize bool
+		input     map[string]any
+		check     func(t *testing.T, params map[string]any)
+	}{
+		{
+			name:      "no env vars key",
+			anonymize: false,
+			input:     map[string]any{"management_url": "https://mgmt.example.com"},
+			check: func(t *testing.T, params map[string]any) {
+				t.Helper()
+				assert.Equal(t, "https://mgmt.example.com", params["management_url"], "non-env fields should be untouched")
+				_, ok := params[jsonKeyServiceEnv]
+				assert.False(t, ok, "service_env_vars should not be added")
+			},
+		},
+		{
+			name:      "non-NB vars are masked",
+			anonymize: false,
+			input: map[string]any{
+				jsonKeyServiceEnv: map[string]any{
+					"HOME":       "/root",
+					"PATH":       "/usr/bin",
+					"NB_LOG_LEVEL": "debug",
+				},
+			},
+			check: func(t *testing.T, params map[string]any) {
+				t.Helper()
+				env := params[jsonKeyServiceEnv].(map[string]any)
+				assert.Equal(t, maskedValue, env["HOME"], "non-NB_ var should be masked")
+				assert.Equal(t, maskedValue, env["PATH"], "non-NB_ var should be masked")
+				assert.Equal(t, "debug", env["NB_LOG_LEVEL"], "safe NB_ var should pass through")
+			},
+		},
+		{
+			name:      "sensitive NB vars are masked",
+			anonymize: false,
+			input: map[string]any{
+				jsonKeyServiceEnv: map[string]any{
+					"NB_SETUP_KEY":  "abc123",
+					"NB_API_TOKEN":  "tok_xyz",
+					"NB_LOG_LEVEL":  "info",
+				},
+			},
+			check: func(t *testing.T, params map[string]any) {
+				t.Helper()
+				env := params[jsonKeyServiceEnv].(map[string]any)
+				assert.Equal(t, maskedValue, env["NB_SETUP_KEY"], "sensitive NB_ var should be masked")
+				assert.Equal(t, maskedValue, env["NB_API_TOKEN"], "sensitive NB_ var should be masked")
+				assert.Equal(t, "info", env["NB_LOG_LEVEL"], "safe NB_ var should pass through")
+			},
+		},
+		{
+			name:      "safe NB vars anonymized when anonymize is true",
+			anonymize: true,
+			input: map[string]any{
+				jsonKeyServiceEnv: map[string]any{
+					"NB_MANAGEMENT_URL": "https://mgmt.example.com:443",
+					"NB_LOG_LEVEL":      "debug",
+					"NB_SETUP_KEY":      "secret",
+					"SOME_OTHER":        "val",
+				},
+			},
+			check: func(t *testing.T, params map[string]any) {
+				t.Helper()
+				env := params[jsonKeyServiceEnv].(map[string]any)
+				// Safe NB_ values should be anonymized (not the original, not masked)
+				mgmtVal := env["NB_MANAGEMENT_URL"].(string)
+				assert.NotEqual(t, "https://mgmt.example.com:443", mgmtVal, "should be anonymized")
+				assert.NotEqual(t, maskedValue, mgmtVal, "should not be masked")
+
+				logVal := env["NB_LOG_LEVEL"].(string)
+				assert.NotEqual(t, maskedValue, logVal, "safe NB_ var should not be masked")
+
+				// Sensitive and non-NB_ still masked
+				assert.Equal(t, maskedValue, env["NB_SETUP_KEY"])
+				assert.Equal(t, maskedValue, env["SOME_OTHER"])
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			anonymizer := anonymize.NewAnonymizer(anonymize.DefaultAddresses())
+			g := &BundleGenerator{
+				anonymize:  tt.anonymize,
+				anonymizer: anonymizer,
+			}
+			g.sanitizeServiceEnvVars(tt.input)
+			tt.check(t, tt.input)
+		})
+	}
+}
+
+func TestAddServiceParams(t *testing.T) {
+	t.Run("missing service.json returns nil", func(t *testing.T) {
+		g := &BundleGenerator{
+			anonymizer: anonymize.NewAnonymizer(anonymize.DefaultAddresses()),
+		}
+
+		origStateDir := configs.StateDir
+		configs.StateDir = t.TempDir()
+		t.Cleanup(func() { configs.StateDir = origStateDir })
+
+		err := g.addServiceParams()
+		assert.NoError(t, err)
+	})
+
+	t.Run("management_url anonymized when anonymize is true", func(t *testing.T) {
+		dir := t.TempDir()
+		origStateDir := configs.StateDir
+		configs.StateDir = dir
+		t.Cleanup(func() { configs.StateDir = origStateDir })
+
+		input := map[string]any{
+			jsonKeyManagementURL: "https://api.example.com:443",
+			jsonKeyServiceEnv: map[string]any{
+				"NB_LOG_LEVEL": "trace",
+			},
+		}
+		data, err := json.Marshal(input)
+		require.NoError(t, err)
+		require.NoError(t, os.WriteFile(filepath.Join(dir, serviceParamsFile), data, 0600))
+
+		var buf bytes.Buffer
+		zw := zip.NewWriter(&buf)
+
+		g := &BundleGenerator{
+			anonymize:  true,
+			anonymizer: anonymize.NewAnonymizer(anonymize.DefaultAddresses()),
+			archive:    zw,
+		}
+
+		require.NoError(t, g.addServiceParams())
+		require.NoError(t, zw.Close())
+
+		zr, err := zip.NewReader(bytes.NewReader(buf.Bytes()), int64(buf.Len()))
+		require.NoError(t, err)
+		require.Len(t, zr.File, 1)
+		assert.Equal(t, serviceParamsBundle, zr.File[0].Name)
+
+		rc, err := zr.File[0].Open()
+		require.NoError(t, err)
+		defer rc.Close()
+
+		var result map[string]any
+		require.NoError(t, json.NewDecoder(rc).Decode(&result))
+
+		mgmt := result[jsonKeyManagementURL].(string)
+		assert.NotEqual(t, "https://api.example.com:443", mgmt, "management_url should be anonymized")
+		assert.NotEmpty(t, mgmt)
+
+		env := result[jsonKeyServiceEnv].(map[string]any)
+		assert.NotEqual(t, maskedValue, env["NB_LOG_LEVEL"], "safe NB_ var should not be masked")
+	})
+
+	t.Run("management_url preserved when anonymize is false", func(t *testing.T) {
+		dir := t.TempDir()
+		origStateDir := configs.StateDir
+		configs.StateDir = dir
+		t.Cleanup(func() { configs.StateDir = origStateDir })
+
+		input := map[string]any{
+			jsonKeyManagementURL: "https://api.example.com:443",
+		}
+		data, err := json.Marshal(input)
+		require.NoError(t, err)
+		require.NoError(t, os.WriteFile(filepath.Join(dir, serviceParamsFile), data, 0600))
+
+		var buf bytes.Buffer
+		zw := zip.NewWriter(&buf)
+
+		g := &BundleGenerator{
+			anonymize:  false,
+			anonymizer: anonymize.NewAnonymizer(anonymize.DefaultAddresses()),
+			archive:    zw,
+		}
+
+		require.NoError(t, g.addServiceParams())
+		require.NoError(t, zw.Close())
+
+		zr, err := zip.NewReader(bytes.NewReader(buf.Bytes()), int64(buf.Len()))
+		require.NoError(t, err)
+
+		rc, err := zr.File[0].Open()
+		require.NoError(t, err)
+		defer rc.Close()
+
+		var result map[string]any
+		require.NoError(t, json.NewDecoder(rc).Decode(&result))
+
+		assert.Equal(t, "https://api.example.com:443", result[jsonKeyManagementURL], "management_url should be preserved")
+	})
+}
+
 // Helper function to check if IP is in CGNAT range
 func isInCGNATRange(ip net.IP) bool {
 	cgnat := net.IPNet{

client/internal/debug/upload_test.go

@@ -3,10 +3,12 @@ package debug
 import (
 	"context"
 	"errors"
+	"net"
 	"net/http"
 	"os"
 	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
 
@@ -19,8 +21,10 @@ func TestUpload(t *testing.T) {
 		t.Skip("Skipping upload test on docker ci")
 	}
 	testDir := t.TempDir()
-	testURL := "http://localhost:8080"
+	addr := reserveLoopbackPort(t)
+	testURL := "http://" + addr
 	t.Setenv("SERVER_URL", testURL)
+	t.Setenv("SERVER_ADDRESS", addr)
 	t.Setenv("STORE_DIR", testDir)
 	srv := server.NewServer()
 	go func() {
@@ -33,6 +37,7 @@ func TestUpload(t *testing.T) {
 			t.Errorf("Failed to stop server: %v", err)
 		}
 	})
+	waitForServer(t, addr)
 
 	file := filepath.Join(t.TempDir(), "tmpfile")
 	fileContent := []byte("test file content")
@@ -47,3 +52,30 @@ func TestUpload(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, fileContent, createdFileContent)
 }
+
+// reserveLoopbackPort binds an ephemeral port on loopback to learn a free
+// address, then releases it so the server under test can rebind. The close/
+// rebind window is racy in theory; on loopback with a kernel-assigned port
+// it's essentially never contended in practice.
+func reserveLoopbackPort(t *testing.T) string {
+	t.Helper()
+	l, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+	addr := l.Addr().String()
+	require.NoError(t, l.Close())
+	return addr
+}
+
+func waitForServer(t *testing.T, addr string) {
+	t.Helper()
+	deadline := time.Now().Add(5 * time.Second)
+	for time.Now().Before(deadline) {
+		c, err := net.DialTimeout("tcp", addr, 100*time.Millisecond)
+		if err == nil {
+			_ = c.Close()
+			return
+		}
+		time.Sleep(20 * time.Millisecond)
+	}
+	t.Fatalf("server did not start listening on %s in time", addr)
+}

client/internal/dns/file_parser_unix.go

@@ -13,6 +13,7 @@ import (
 
 const (
 	defaultResolvConfPath = "/etc/resolv.conf"
+	nsswitchConfPath      = "/etc/nsswitch.conf"
 )
 
 type resolvConf struct {

client/internal/dns/handler_chain.go

@@ -1,7 +1,10 @@
 package dns
 
 import (
+	"context"
 	"fmt"
+	"math"
+	"net"
 	"slices"
 	"strconv"
 	"strings"
@@ -73,6 +76,9 @@ func (w *ResponseWriterChain) WriteMsg(m *dns.Msg) error {
 		return nil
 	}
 	w.response = m
+	if m.MsgHdr.Truncated {
+		w.SetMeta("truncated", "true")
+	}
 	return w.ResponseWriter.WriteMsg(m)
 }
 
@@ -189,16 +195,26 @@ func (c *HandlerChain) logHandlers() {
 }
 
 func (c *HandlerChain) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
+	c.dispatch(w, r, math.MaxInt)
+}
+
+// dispatch routes a DNS request through the chain, skipping handlers with
+// priority > maxPriority. Shared by ServeDNS and ResolveInternal.
+func (c *HandlerChain) dispatch(w dns.ResponseWriter, r *dns.Msg, maxPriority int) {
 	if len(r.Question) == 0 {
 		return
 	}
 
 	startTime := time.Now()
 	requestID := resutil.GenerateRequestID()
-	logger := log.WithFields(log.Fields{
+	fields := log.Fields{
 		"request_id": requestID,
 		"dns_id":     fmt.Sprintf("%04x", r.Id),
-	})
+	}
+	if addr := w.RemoteAddr(); addr != nil {
+		fields["client"] = addr.String()
+	}
+	logger := log.WithFields(fields)
 
 	question := r.Question[0]
 	qname := strings.ToLower(question.Name)
@@ -209,6 +225,9 @@ func (c *HandlerChain) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 
 	// Try handlers in priority order
 	for _, entry := range handlers {
+		if entry.Priority > maxPriority {
+			continue
+		}
 		if !c.isHandlerMatch(qname, entry) {
 			continue
 		}
@@ -261,9 +280,58 @@ func (c *HandlerChain) logResponse(logger *log.Entry, cw *ResponseWriterChain, q
 		meta += " " + k + "=" + v
 	}
 
-	logger.Tracef("response: domain=%s rcode=%s answers=%s%s took=%s",
+	logger.Tracef("response: domain=%s rcode=%s answers=%s size=%dB%s took=%s",
 		qname, dns.RcodeToString[cw.response.Rcode], resutil.FormatAnswers(cw.response.Answer),
-		meta, time.Since(startTime))
+		cw.response.Len(), meta, time.Since(startTime))
+}
+
+// ResolveInternal runs an in-process DNS query against the chain, skipping any
+// handler with priority > maxPriority. Used by internal callers (e.g. the mgmt
+// cache refresher) that must bypass themselves to avoid loops. Honors ctx
+// cancellation; on ctx.Done the dispatch goroutine is left to drain on its own
+// (bounded by the invoked handler's internal timeout).
+func (c *HandlerChain) ResolveInternal(ctx context.Context, r *dns.Msg, maxPriority int) (*dns.Msg, error) {
+	if len(r.Question) == 0 {
+		return nil, fmt.Errorf("empty question")
+	}
+
+	base := &internalResponseWriter{}
+	done := make(chan struct{})
+	go func() {
+		c.dispatch(base, r, maxPriority)
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-ctx.Done():
+		// Prefer a completed response if dispatch finished concurrently with cancellation.
+		select {
+		case <-done:
+		default:
+			return nil, fmt.Errorf("resolve %s: %w", strings.ToLower(r.Question[0].Name), ctx.Err())
+		}
+	}
+
+	if base.response == nil || base.response.Rcode == dns.RcodeRefused {
+		return nil, fmt.Errorf("no handler resolved %s at priority ≤ %d",
+			strings.ToLower(r.Question[0].Name), maxPriority)
+	}
+	return base.response, nil
+}
+
+// HasRootHandlerAtOrBelow reports whether any "." handler is registered at
+// priority ≤ maxPriority.
+func (c *HandlerChain) HasRootHandlerAtOrBelow(maxPriority int) bool {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	for _, h := range c.handlers {
+		if h.Pattern == "." && h.Priority <= maxPriority {
+			return true
+		}
+	}
+	return false
 }
 
 func (c *HandlerChain) isHandlerMatch(qname string, entry HandlerEntry) bool {
@@ -284,3 +352,36 @@ func (c *HandlerChain) isHandlerMatch(qname string, entry HandlerEntry) bool {
 		}
 	}
 }
+
+// internalResponseWriter captures a dns.Msg for in-process chain queries.
+type internalResponseWriter struct {
+	response *dns.Msg
+}
+
+func (w *internalResponseWriter) WriteMsg(m *dns.Msg) error { w.response = m; return nil }
+func (w *internalResponseWriter) LocalAddr() net.Addr       { return nil }
+func (w *internalResponseWriter) RemoteAddr() net.Addr      { return nil }
+
+// Write unpacks raw DNS bytes so handlers that call Write instead of WriteMsg
+// still surface their answer to ResolveInternal.
+func (w *internalResponseWriter) Write(p []byte) (int, error) {
+	msg := new(dns.Msg)
+	if err := msg.Unpack(p); err != nil {
+		return 0, err
+	}
+	w.response = msg
+	return len(p), nil
+}
+
+func (w *internalResponseWriter) Close() error      { return nil }
+func (w *internalResponseWriter) TsigStatus() error { return nil }
+
+// TsigTimersOnly is part of dns.ResponseWriter.
+func (w *internalResponseWriter) TsigTimersOnly(bool) {
+	// no-op: in-process queries carry no TSIG state.
+}
+
+// Hijack is part of dns.ResponseWriter.
+func (w *internalResponseWriter) Hijack() {
+	// no-op: in-process queries have no underlying connection to hand off.
+}

client/internal/dns/handler_chain_test.go

@@ -1,11 +1,15 @@
 package dns_test
 
 import (
+	"context"
+	"net"
 	"testing"
+	"time"
 
 	"github.com/miekg/dns"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
 
 	nbdns "github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/dns/test"
@@ -1042,3 +1046,163 @@ func TestHandlerChain_AddRemoveRoundtrip(t *testing.T) {
 		})
 	}
 }
+
+// answeringHandler writes a fixed A record to ack the query. Used to verify
+// which handler ResolveInternal dispatches to.
+type answeringHandler struct {
+	name string
+	ip   string
+}
+
+func (h *answeringHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
+	resp := &dns.Msg{}
+	resp.SetReply(r)
+	resp.Answer = []dns.RR{&dns.A{
+		Hdr: dns.RR_Header{Name: r.Question[0].Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+		A:   net.ParseIP(h.ip).To4(),
+	}}
+	_ = w.WriteMsg(resp)
+}
+
+func (h *answeringHandler) String() string { return h.name }
+
+func TestHandlerChain_ResolveInternal_SkipsAboveMaxPriority(t *testing.T) {
+	chain := nbdns.NewHandlerChain()
+
+	high := &answeringHandler{name: "high", ip: "10.0.0.1"}
+	low := &answeringHandler{name: "low", ip: "10.0.0.2"}
+
+	chain.AddHandler("example.com.", high, nbdns.PriorityMgmtCache)
+	chain.AddHandler("example.com.", low, nbdns.PriorityUpstream)
+
+	r := new(dns.Msg)
+	r.SetQuestion("example.com.", dns.TypeA)
+
+	resp, err := chain.ResolveInternal(context.Background(), r, nbdns.PriorityUpstream)
+	assert.NoError(t, err)
+	assert.NotNil(t, resp)
+	assert.Equal(t, 1, len(resp.Answer))
+	a, ok := resp.Answer[0].(*dns.A)
+	assert.True(t, ok)
+	assert.Equal(t, "10.0.0.2", a.A.String(), "should skip mgmtCache handler and resolve via upstream")
+}
+
+func TestHandlerChain_ResolveInternal_ErrorWhenNoMatch(t *testing.T) {
+	chain := nbdns.NewHandlerChain()
+	high := &answeringHandler{name: "high", ip: "10.0.0.1"}
+	chain.AddHandler("example.com.", high, nbdns.PriorityMgmtCache)
+
+	r := new(dns.Msg)
+	r.SetQuestion("example.com.", dns.TypeA)
+
+	_, err := chain.ResolveInternal(context.Background(), r, nbdns.PriorityUpstream)
+	assert.Error(t, err, "no handler at or below maxPriority should error")
+}
+
+// rawWriteHandler packs a response and calls ResponseWriter.Write directly
+// (instead of WriteMsg), exercising the internalResponseWriter.Write path.
+type rawWriteHandler struct {
+	ip string
+}
+
+func (h *rawWriteHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
+	resp := &dns.Msg{}
+	resp.SetReply(r)
+	resp.Answer = []dns.RR{&dns.A{
+		Hdr: dns.RR_Header{Name: r.Question[0].Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+		A:   net.ParseIP(h.ip).To4(),
+	}}
+	packed, err := resp.Pack()
+	if err != nil {
+		return
+	}
+	_, _ = w.Write(packed)
+}
+
+func TestHandlerChain_ResolveInternal_CapturesRawWrite(t *testing.T) {
+	chain := nbdns.NewHandlerChain()
+	chain.AddHandler("example.com.", &rawWriteHandler{ip: "10.0.0.3"}, nbdns.PriorityUpstream)
+
+	r := new(dns.Msg)
+	r.SetQuestion("example.com.", dns.TypeA)
+
+	resp, err := chain.ResolveInternal(context.Background(), r, nbdns.PriorityUpstream)
+	assert.NoError(t, err)
+	require.NotNil(t, resp)
+	require.Len(t, resp.Answer, 1)
+	a, ok := resp.Answer[0].(*dns.A)
+	require.True(t, ok)
+	assert.Equal(t, "10.0.0.3", a.A.String(), "handlers calling Write(packed) must still surface their answer")
+}
+
+func TestHandlerChain_ResolveInternal_EmptyQuestion(t *testing.T) {
+	chain := nbdns.NewHandlerChain()
+	_, err := chain.ResolveInternal(context.Background(), new(dns.Msg), nbdns.PriorityUpstream)
+	assert.Error(t, err)
+}
+
+// hangingHandler blocks indefinitely until closed, simulating a wedged upstream.
+type hangingHandler struct {
+	block chan struct{}
+}
+
+func (h *hangingHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
+	<-h.block
+	resp := &dns.Msg{}
+	resp.SetReply(r)
+	_ = w.WriteMsg(resp)
+}
+
+func (h *hangingHandler) String() string { return "hangingHandler" }
+
+func TestHandlerChain_ResolveInternal_HonorsContextTimeout(t *testing.T) {
+	chain := nbdns.NewHandlerChain()
+	h := &hangingHandler{block: make(chan struct{})}
+	defer close(h.block)
+
+	chain.AddHandler("example.com.", h, nbdns.PriorityUpstream)
+
+	r := new(dns.Msg)
+	r.SetQuestion("example.com.", dns.TypeA)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+
+	start := time.Now()
+	_, err := chain.ResolveInternal(ctx, r, nbdns.PriorityUpstream)
+	elapsed := time.Since(start)
+
+	assert.Error(t, err)
+	assert.ErrorIs(t, err, context.DeadlineExceeded)
+	assert.Less(t, elapsed, 500*time.Millisecond, "ResolveInternal must return shortly after ctx deadline")
+}
+
+func TestHandlerChain_HasRootHandlerAtOrBelow(t *testing.T) {
+	chain := nbdns.NewHandlerChain()
+	h := &answeringHandler{name: "h", ip: "10.0.0.1"}
+
+	assert.False(t, chain.HasRootHandlerAtOrBelow(nbdns.PriorityUpstream), "empty chain")
+
+	chain.AddHandler("example.com.", h, nbdns.PriorityUpstream)
+	assert.False(t, chain.HasRootHandlerAtOrBelow(nbdns.PriorityUpstream), "non-root handler does not count")
+
+	chain.AddHandler(".", h, nbdns.PriorityMgmtCache)
+	assert.False(t, chain.HasRootHandlerAtOrBelow(nbdns.PriorityUpstream), "root handler above threshold excluded")
+
+	chain.AddHandler(".", h, nbdns.PriorityDefault)
+	assert.True(t, chain.HasRootHandlerAtOrBelow(nbdns.PriorityUpstream), "root handler at PriorityDefault included")
+
+	chain.RemoveHandler(".", nbdns.PriorityDefault)
+	assert.False(t, chain.HasRootHandlerAtOrBelow(nbdns.PriorityUpstream))
+
+	// Primary nsgroup case: root handler lands at PriorityUpstream.
+	chain.AddHandler(".", h, nbdns.PriorityUpstream)
+	assert.True(t, chain.HasRootHandlerAtOrBelow(nbdns.PriorityUpstream), "root at PriorityUpstream included")
+	chain.RemoveHandler(".", nbdns.PriorityUpstream)
+
+	// Fallback case: original /etc/resolv.conf entries land at PriorityFallback.
+	chain.AddHandler(".", h, nbdns.PriorityFallback)
+	assert.True(t, chain.HasRootHandlerAtOrBelow(nbdns.PriorityUpstream), "root at PriorityFallback included")
+	chain.RemoveHandler(".", nbdns.PriorityFallback)
+	assert.False(t, chain.HasRootHandlerAtOrBelow(nbdns.PriorityUpstream))
+}

client/internal/dns/host_unix.go

@@ -46,12 +46,12 @@ type restoreHostManager interface {
 }
 
 func newHostManager(wgInterface string) (hostManager, error) {
-	osManager, err := getOSDNSManagerType()
+	osManager, reason, err := getOSDNSManagerType()
 	if err != nil {
 		return nil, fmt.Errorf("get os dns manager type: %w", err)
 	}
 
-	log.Infof("System DNS manager discovered: %s", osManager)
+	log.Infof("System DNS manager discovered: %s (%s)", osManager, reason)
 	mgr, err := newHostManagerFromType(wgInterface, osManager)
 	// need to explicitly return nil mgr on error to avoid returning a non-nil interface containing a nil value
 	if err != nil {
@@ -74,17 +74,49 @@ func newHostManagerFromType(wgInterface string, osManager osManagerType) (restor
 	}
 }
 
-func getOSDNSManagerType() (osManagerType, error) {
+func getOSDNSManagerType() (osManagerType, string, error) {
+	resolved := isSystemdResolvedRunning()
+	nss := isLibnssResolveUsed()
+	stub := checkStub()
+
+	// Prefer systemd-resolved whenever it owns libc resolution, regardless of
+	// who wrote /etc/resolv.conf. File-mode rewrites do not affect lookups
+	// that go through nss-resolve, and in foreign mode they can loop back
+	// through resolved as an upstream.
+	if resolved && (nss || stub) {
+		return systemdManager, fmt.Sprintf("systemd-resolved active (nss-resolve=%t, stub=%t)", nss, stub), nil
+	}
+
+	mgr, reason, rejected, err := scanResolvConfHeader()
+	if err != nil {
+		return 0, "", err
+	}
+	if reason != "" {
+		return mgr, reason, nil
+	}
+
+	fallback := fmt.Sprintf("no manager matched (resolved=%t, nss-resolve=%t, stub=%t)", resolved, nss, stub)
+	if len(rejected) > 0 {
+		fallback += "; rejected: " + strings.Join(rejected, ", ")
+	}
+	return fileManager, fallback, nil
+}
+
+// scanResolvConfHeader walks /etc/resolv.conf header comments and returns the
+// matching manager. If reason is empty the caller should pick file mode and
+// use rejected for diagnostics.
+func scanResolvConfHeader() (osManagerType, string, []string, error) {
 	file, err := os.Open(defaultResolvConfPath)
 	if err != nil {
-		return 0, fmt.Errorf("unable to open %s for checking owner, got error: %w", defaultResolvConfPath, err)
+		return 0, "", nil, fmt.Errorf("unable to open %s for checking owner, got error: %w", defaultResolvConfPath, err)
 	}
 	defer func() {
-		if err := file.Close(); err != nil {
-			log.Errorf("close file %s: %s", defaultResolvConfPath, err)
+		if cerr := file.Close(); cerr != nil {
+			log.Errorf("close file %s: %s", defaultResolvConfPath, cerr)
 		}
 	}()
 
+	var rejected []string
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
 		text := scanner.Text()
@@ -92,41 +124,48 @@ func getOSDNSManagerType() (osManagerType, error) {
 			continue
 		}
 		if text[0] != '#' {
-			return fileManager, nil
+			break
 		}
-		if strings.Contains(text, fileGeneratedResolvConfContentHeader) {
-			return netbirdManager, nil
-		}
-		if strings.Contains(text, "NetworkManager") && isDbusListenerRunning(networkManagerDest, networkManagerDbusObjectNode) && isNetworkManagerSupported() {
-			return networkManager, nil
-		}
-		if strings.Contains(text, "systemd-resolved") && isSystemdResolvedRunning() {
-			if checkStub() {
-				return systemdManager, nil
-			} else {
-				return fileManager, nil
-			}
-		}
-		if strings.Contains(text, "resolvconf") {
-			if isSystemdResolveConfMode() {
-				return systemdManager, nil
-			}
-
-			return resolvConfManager, nil
+		if mgr, reason, rej := matchResolvConfHeader(text); reason != "" {
+			return mgr, reason, nil, nil
+		} else if rej != "" {
+			rejected = append(rejected, rej)
 		}
 	}
 	if err := scanner.Err(); err != nil && err != io.EOF {
-		return 0, fmt.Errorf("scan: %w", err)
+		return 0, "", nil, fmt.Errorf("scan: %w", err)
 	}
-
-	return fileManager, nil
+	return 0, "", rejected, nil
 }
 
-// checkStub checks if the stub resolver is disabled in systemd-resolved. If it is disabled, we fall back to file manager.
+// matchResolvConfHeader inspects a single comment line. Returns either a
+// definitive (manager, reason) or a non-empty rejected diagnostic.
+func matchResolvConfHeader(text string) (osManagerType, string, string) {
+	if strings.Contains(text, fileGeneratedResolvConfContentHeader) {
+		return netbirdManager, "netbird-managed resolv.conf header detected", ""
+	}
+	if strings.Contains(text, "NetworkManager") {
+		if isDbusListenerRunning(networkManagerDest, networkManagerDbusObjectNode) && isNetworkManagerSupported() {
+			return networkManager, "NetworkManager header + supported version on dbus", ""
+		}
+		return 0, "", "NetworkManager header (no dbus or unsupported version)"
+	}
+	if strings.Contains(text, "resolvconf") {
+		if isSystemdResolveConfMode() {
+			return systemdManager, "resolvconf header in systemd-resolved compatibility mode", ""
+		}
+		return resolvConfManager, "resolvconf header detected", ""
+	}
+	return 0, "", ""
+}
+
+// checkStub reports whether systemd-resolved's stub (127.0.0.53) is listed
+// in /etc/resolv.conf. On parse failure we assume it is, to avoid dropping
+// into file mode while resolved is active.
 func checkStub() bool {
 	rConf, err := parseDefaultResolvConf()
 	if err != nil {
-		log.Warnf("failed to parse resolv conf: %s", err)
+		log.Warnf("failed to parse resolv conf, assuming stub is active: %s", err)
 		return true
 	}
 
@@ -139,3 +178,36 @@ func checkStub() bool {
 
 	return false
 }
+
+// isLibnssResolveUsed reports whether nss-resolve is listed before dns on
+// the hosts: line of /etc/nsswitch.conf. When it is, libc lookups are
+// delegated to systemd-resolved regardless of /etc/resolv.conf.
+func isLibnssResolveUsed() bool {
+	bs, err := os.ReadFile(nsswitchConfPath)
+	if err != nil {
+		log.Debugf("read %s: %v", nsswitchConfPath, err)
+		return false
+	}
+	return parseNsswitchResolveAhead(bs)
+}
+
+func parseNsswitchResolveAhead(data []byte) bool {
+	for _, line := range strings.Split(string(data), "\n") {
+		if i := strings.IndexByte(line, '#'); i >= 0 {
+			line = line[:i]
+		}
+		fields := strings.Fields(line)
+		if len(fields) < 2 || fields[0] != "hosts:" {
+			continue
+		}
+		for _, module := range fields[1:] {
+			switch module {
+			case "dns":
+				return false
+			case "resolve":
+				return true
+			}
+		}
+	}
+	return false
+}

client/internal/dns/host_unix_test.go

@@ -0,0 +1,76 @@
+//go:build (linux && !android) || freebsd
+
+package dns
+
+import "testing"
+
+func TestParseNsswitchResolveAhead(t *testing.T) {
+	tests := []struct {
+		name string
+		in   string
+		want bool
+	}{
+		{
+			name: "resolve before dns with action token",
+			in:   "hosts: mymachines resolve [!UNAVAIL=return] files myhostname dns\n",
+			want: true,
+		},
+		{
+			name: "dns before resolve",
+			in:   "hosts: files mdns4_minimal [NOTFOUND=return] dns resolve\n",
+			want: false,
+		},
+		{
+			name: "debian default with only dns",
+			in:   "hosts: files mdns4_minimal [NOTFOUND=return] dns mymachines\n",
+			want: false,
+		},
+		{
+			name: "neither resolve nor dns",
+			in:   "hosts: files myhostname\n",
+			want: false,
+		},
+		{
+			name: "no hosts line",
+			in:   "passwd: files systemd\ngroup: files systemd\n",
+			want: false,
+		},
+		{
+			name: "empty",
+			in:   "",
+			want: false,
+		},
+		{
+			name: "comments and blank lines ignored",
+			in:   "# comment\n\n# another\nhosts: resolve dns\n",
+			want: true,
+		},
+		{
+			name: "trailing inline comment",
+			in:   "hosts: resolve [!UNAVAIL=return] dns # fallback\n",
+			want: true,
+		},
+		{
+			name: "hosts token must be the first field",
+			in:   "  hosts: resolve dns\n",
+			want: true,
+		},
+		{
+			name: "other db line mentioning resolve is ignored",
+			in:   "networks: resolve\nhosts: dns\n",
+			want: false,
+		},
+		{
+			name: "only resolve, no dns",
+			in:   "hosts: files resolve\n",
+			want: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := parseNsswitchResolveAhead([]byte(tt.in)); got != tt.want {
+				t.Errorf("parseNsswitchResolveAhead() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

client/internal/dns/local/local_test.go

@@ -1263,9 +1263,9 @@ func TestLocalResolver_AuthoritativeFlag(t *testing.T) {
 	})
 }
 
-// TestLocalResolver_Stop tests cleanup on Stop
+// TestLocalResolver_Stop tests cleanup on GracefullyStop
 func TestLocalResolver_Stop(t *testing.T) {
-	t.Run("Stop clears all state", func(t *testing.T) {
+	t.Run("GracefullyStop clears all state", func(t *testing.T) {
 		resolver := NewResolver()
 		resolver.Update([]nbdns.CustomZone{{
 			Domain: "example.com.",
@@ -1285,7 +1285,7 @@ func TestLocalResolver_Stop(t *testing.T) {
 		assert.False(t, resolver.isInManagedZone("host.example.com."))
 	})
 
-	t.Run("Stop is safe to call multiple times", func(t *testing.T) {
+	t.Run("GracefullyStop is safe to call multiple times", func(t *testing.T) {
 		resolver := NewResolver()
 		resolver.Update([]nbdns.CustomZone{{
 			Domain: "example.com.",
@@ -1299,7 +1299,7 @@ func TestLocalResolver_Stop(t *testing.T) {
 		resolver.Stop()
 	})
 
-	t.Run("Stop cancels in-flight external resolution", func(t *testing.T) {
+	t.Run("GracefullyStop cancels in-flight external resolution", func(t *testing.T) {
 		resolver := NewResolver()
 
 		lookupStarted := make(chan struct{})

client/internal/dns/mgmt/mgmt.go

@@ -2,40 +2,83 @@ package mgmt
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net"
-	"net/netip"
 	"net/url"
+	"os"
+	"slices"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/miekg/dns"
 	log "github.com/sirupsen/logrus"
+	"golang.org/x/sync/singleflight"
 
 	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
+	"github.com/netbirdio/netbird/client/internal/dns/resutil"
 	"github.com/netbirdio/netbird/shared/management/domain"
 )
 
-const dnsTimeout = 5 * time.Second
+const (
+	dnsTimeout     = 5 * time.Second
+	defaultTTL     = 300 * time.Second
+	refreshBackoff = 30 * time.Second
 
-// Resolver caches critical NetBird infrastructure domains
+	// envMgmtCacheTTL overrides defaultTTL for integration/dev testing.
+	envMgmtCacheTTL = "NB_MGMT_CACHE_TTL"
+)
+
+// ChainResolver lets the cache refresh stale entries through the DNS handler
+// chain instead of net.DefaultResolver, avoiding loopback when NetBird is the
+// system resolver.
+type ChainResolver interface {
+	ResolveInternal(ctx context.Context, msg *dns.Msg, maxPriority int) (*dns.Msg, error)
+	HasRootHandlerAtOrBelow(maxPriority int) bool
+}
+
+// cachedRecord holds DNS records plus timestamps used for TTL refresh.
+// records and cachedAt are set at construction and treated as immutable;
+// lastFailedRefresh and consecFailures are mutable and must be accessed under
+// Resolver.mutex.
+type cachedRecord struct {
+	records           []dns.RR
+	cachedAt          time.Time
+	lastFailedRefresh time.Time
+	consecFailures    int
+}
+
+// Resolver caches critical NetBird infrastructure domains.
+// records, refreshing, mgmtDomain and serverDomains are all guarded by mutex.
 type Resolver struct {
-	records       map[dns.Question][]dns.RR
+	records       map[dns.Question]*cachedRecord
 	mgmtDomain    *domain.Domain
 	serverDomains *dnsconfig.ServerDomains
 	mutex         sync.RWMutex
-}
 
-type ipsResponse struct {
-	ips []netip.Addr
-	err error
+	chain            ChainResolver
+	chainMaxPriority int
+	refreshGroup     singleflight.Group
+
+	// refreshing tracks questions whose refresh is running via the OS
+	// fallback path. A ServeDNS hit for a question in this map indicates
+	// the OS resolver routed the recursive query back to us (loop). Only
+	// the OS path arms this so chain-path refreshes don't produce false
+	// positives. The atomic bool is CAS-flipped once per refresh to
+	// throttle the warning log.
+	refreshing map[dns.Question]*atomic.Bool
+
+	cacheTTL time.Duration
 }
 
 // NewResolver creates a new management domains cache resolver.
 func NewResolver() *Resolver {
 	return &Resolver{
-		records: make(map[dns.Question][]dns.RR),
+		records:    make(map[dns.Question]*cachedRecord),
+		refreshing: make(map[dns.Question]*atomic.Bool),
+		cacheTTL:   resolveCacheTTL(),
 	}
 }
 
@@ -44,7 +87,19 @@ func (m *Resolver) String() string {
 	return "MgmtCacheResolver"
 }
 
-// ServeDNS implements dns.Handler interface.
+// SetChainResolver wires the handler chain used to refresh stale cache entries.
+// maxPriority caps which handlers may answer refresh queries (typically
+// PriorityUpstream, so upstream/default/fallback handlers are consulted and
+// mgmt/route/local handlers are skipped).
+func (m *Resolver) SetChainResolver(chain ChainResolver, maxPriority int) {
+	m.mutex.Lock()
+	m.chain = chain
+	m.chainMaxPriority = maxPriority
+	m.mutex.Unlock()
+}
+
+// ServeDNS serves cached A/AAAA records. Stale entries are returned
+// immediately and refreshed asynchronously (stale-while-revalidate).
 func (m *Resolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	if len(r.Question) == 0 {
 		m.continueToNext(w, r)
@@ -60,7 +115,14 @@ func (m *Resolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	}
 
 	m.mutex.RLock()
-	records, found := m.records[question]
+	cached, found := m.records[question]
+	inflight := m.refreshing[question]
+	var shouldRefresh bool
+	if found {
+		stale := time.Since(cached.cachedAt) > m.cacheTTL
+		inBackoff := !cached.lastFailedRefresh.IsZero() && time.Since(cached.lastFailedRefresh) < refreshBackoff
+		shouldRefresh = stale && !inBackoff
+	}
 	m.mutex.RUnlock()
 
 	if !found {
@@ -68,12 +130,23 @@ func (m *Resolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 		return
 	}
 
+	if inflight != nil && inflight.CompareAndSwap(false, true) {
+		log.Warnf("mgmt cache: possible resolver loop for domain=%s: served stale while an OS-fallback refresh was inflight (if NetBird is the system resolver, the OS-path predicate is wrong)",
+			question.Name)
+	}
+
+	// Skip scheduling a refresh goroutine if one is already inflight for
+	// this question; singleflight would dedup anyway but skipping avoids
+	// a parked goroutine per stale hit under bursty load.
+	if shouldRefresh && inflight == nil {
+		m.scheduleRefresh(question, cached)
+	}
+
 	resp := &dns.Msg{}
 	resp.SetReply(r)
 	resp.Authoritative = false
 	resp.RecursionAvailable = true
-
-	resp.Answer = append(resp.Answer, records...)
+	resp.Answer = cloneRecordsWithTTL(cached.records, m.responseTTL(cached.cachedAt))
 
 	log.Debugf("serving %d cached records for domain=%s", len(resp.Answer), question.Name)
 
@@ -98,101 +171,260 @@ func (m *Resolver) continueToNext(w dns.ResponseWriter, r *dns.Msg) {
 	}
 }
 
-// AddDomain manually adds a domain to cache by resolving it.
+// AddDomain resolves a domain and stores its A/AAAA records in the cache.
+// A family that resolves NODATA (nil err, zero records) evicts any stale
+// entry for that qtype.
 func (m *Resolver) AddDomain(ctx context.Context, d domain.Domain) error {
 	dnsName := strings.ToLower(dns.Fqdn(d.PunycodeString()))
 
 	ctx, cancel := context.WithTimeout(ctx, dnsTimeout)
 	defer cancel()
 
-	ips, err := lookupIPWithExtraTimeout(ctx, d)
-	if err != nil {
-		return err
+	aRecords, aaaaRecords, errA, errAAAA := m.lookupBoth(ctx, d, dnsName)
+
+	if errA != nil && errAAAA != nil {
+		return fmt.Errorf("resolve %s: %w", d.SafeString(), errors.Join(errA, errAAAA))
 	}
 
-	var aRecords, aaaaRecords []dns.RR
-	for _, ip := range ips {
-		if ip.Is4() {
-			rr := &dns.A{
-				Hdr: dns.RR_Header{
-					Name:   dnsName,
-					Rrtype: dns.TypeA,
-					Class:  dns.ClassINET,
-					Ttl:    300,
-				},
-				A: ip.AsSlice(),
-			}
-			aRecords = append(aRecords, rr)
-		} else if ip.Is6() {
-			rr := &dns.AAAA{
-				Hdr: dns.RR_Header{
-					Name:   dnsName,
-					Rrtype: dns.TypeAAAA,
-					Class:  dns.ClassINET,
-					Ttl:    300,
-				},
-				AAAA: ip.AsSlice(),
-			}
-			aaaaRecords = append(aaaaRecords, rr)
+	if len(aRecords) == 0 && len(aaaaRecords) == 0 {
+		if err := errors.Join(errA, errAAAA); err != nil {
+			return fmt.Errorf("resolve %s: no A/AAAA records: %w", d.SafeString(), err)
 		}
+		return fmt.Errorf("resolve %s: no A/AAAA records", d.SafeString())
 	}
 
+	now := time.Now()
 	m.mutex.Lock()
+	defer m.mutex.Unlock()
 
-	if len(aRecords) > 0 {
-		aQuestion := dns.Question{
-			Name:   dnsName,
-			Qtype:  dns.TypeA,
-			Qclass: dns.ClassINET,
-		}
-		m.records[aQuestion] = aRecords
-	}
+	m.applyFamilyRecords(dnsName, dns.TypeA, aRecords, errA, now)
+	m.applyFamilyRecords(dnsName, dns.TypeAAAA, aaaaRecords, errAAAA, now)
 
-	if len(aaaaRecords) > 0 {
-		aaaaQuestion := dns.Question{
-			Name:   dnsName,
-			Qtype:  dns.TypeAAAA,
-			Qclass: dns.ClassINET,
-		}
-		m.records[aaaaQuestion] = aaaaRecords
-	}
-
-	m.mutex.Unlock()
-
-	log.Debugf("added domain=%s with %d A records and %d AAAA records",
+	log.Debugf("added/updated domain=%s with %d A records and %d AAAA records",
 		d.SafeString(), len(aRecords), len(aaaaRecords))
 
 	return nil
 }
 
-func lookupIPWithExtraTimeout(ctx context.Context, d domain.Domain) ([]netip.Addr, error) {
-	log.Infof("looking up IP for mgmt domain=%s", d.SafeString())
-	defer log.Infof("done looking up IP for mgmt domain=%s", d.SafeString())
-	resultChan := make(chan *ipsResponse, 1)
+// applyFamilyRecords writes records, evicts on NODATA, leaves the cache
+// untouched on error. Caller holds m.mutex.
+func (m *Resolver) applyFamilyRecords(dnsName string, qtype uint16, records []dns.RR, err error, now time.Time) {
+	q := dns.Question{Name: dnsName, Qtype: qtype, Qclass: dns.ClassINET}
+	switch {
+	case len(records) > 0:
+		m.records[q] = &cachedRecord{records: records, cachedAt: now}
+	case err == nil:
+		delete(m.records, q)
+	}
+}
 
-	go func() {
-		ips, err := net.DefaultResolver.LookupNetIP(ctx, "ip", d.PunycodeString())
-		resultChan <- &ipsResponse{
-			err: err,
-			ips: ips,
+// scheduleRefresh kicks off an async refresh. DoChan spawns one goroutine per
+// unique in-flight key; bursty stale hits share its channel. expected is the
+// cachedRecord pointer observed by the caller; the refresh only mutates the
+// cache if that pointer is still the one stored, so a stale in-flight refresh
+// can't clobber a newer entry written by AddDomain or a competing refresh.
+func (m *Resolver) scheduleRefresh(question dns.Question, expected *cachedRecord) {
+	key := question.Name + "|" + dns.TypeToString[question.Qtype]
+	_ = m.refreshGroup.DoChan(key, func() (any, error) {
+		return nil, m.refreshQuestion(question, expected)
+	})
+}
+
+// refreshQuestion replaces the cached records on success, or marks the entry
+// failed (arming the backoff) on failure. While this runs, ServeDNS can detect
+// a resolver loop by spotting a query for this same question arriving on us.
+// expected pins the cache entry observed at schedule time; mutations only apply
+// if m.records[question] still points at it.
+func (m *Resolver) refreshQuestion(question dns.Question, expected *cachedRecord) error {
+	ctx, cancel := context.WithTimeout(context.Background(), dnsTimeout)
+	defer cancel()
+
+	d, err := domain.FromString(strings.TrimSuffix(question.Name, "."))
+	if err != nil {
+		m.markRefreshFailed(question, expected)
+		return fmt.Errorf("parse domain: %w", err)
+	}
+
+	records, err := m.lookupRecords(ctx, d, question)
+	if err != nil {
+		fails := m.markRefreshFailed(question, expected)
+		logf := log.Warnf
+		if fails == 0 || fails > 1 {
+			logf = log.Debugf
 		}
-	}()
-
-	var resp *ipsResponse
-
-	select {
-	case <-time.After(dnsTimeout + time.Millisecond*500):
-		log.Warnf("timed out waiting for IP for mgmt domain=%s", d.SafeString())
-		return nil, fmt.Errorf("timed out waiting for ips to be available for domain %s", d.SafeString())
-	case <-ctx.Done():
-		return nil, ctx.Err()
-	case resp = <-resultChan:
+		logf("refresh mgmt cache domain=%s type=%s: %v (consecutive failures=%d)",
+			d.SafeString(), dns.TypeToString[question.Qtype], err, fails)
+		return err
 	}
 
-	if resp.err != nil {
-		return nil, fmt.Errorf("resolve domain %s: %w", d.SafeString(), resp.err)
+	// NOERROR/NODATA: family gone upstream, evict so we stop serving stale.
+	if len(records) == 0 {
+		m.mutex.Lock()
+		if m.records[question] == expected {
+			delete(m.records, question)
+			m.mutex.Unlock()
+			log.Infof("removed mgmt cache domain=%s type=%s: no records returned",
+				d.SafeString(), dns.TypeToString[question.Qtype])
+			return nil
+		}
+		m.mutex.Unlock()
+		log.Debugf("skipping refresh evict for domain=%s type=%s: entry changed during refresh",
+			d.SafeString(), dns.TypeToString[question.Qtype])
+		return nil
 	}
-	return resp.ips, nil
+
+	now := time.Now()
+	m.mutex.Lock()
+	if m.records[question] != expected {
+		m.mutex.Unlock()
+		log.Debugf("skipping refresh write for domain=%s type=%s: entry changed during refresh",
+			d.SafeString(), dns.TypeToString[question.Qtype])
+		return nil
+	}
+	m.records[question] = &cachedRecord{records: records, cachedAt: now}
+	m.mutex.Unlock()
+
+	log.Infof("refreshed mgmt cache domain=%s type=%s",
+		d.SafeString(), dns.TypeToString[question.Qtype])
+	return nil
+}
+
+func (m *Resolver) markRefreshing(question dns.Question) {
+	m.mutex.Lock()
+	m.refreshing[question] = &atomic.Bool{}
+	m.mutex.Unlock()
+}
+
+func (m *Resolver) clearRefreshing(question dns.Question) {
+	m.mutex.Lock()
+	delete(m.refreshing, question)
+	m.mutex.Unlock()
+}
+
+// markRefreshFailed arms the backoff and returns the new consecutive-failure
+// count so callers can downgrade subsequent failure logs to debug.
+func (m *Resolver) markRefreshFailed(question dns.Question, expected *cachedRecord) int {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	c, ok := m.records[question]
+	if !ok || c != expected {
+		return 0
+	}
+	c.lastFailedRefresh = time.Now()
+	c.consecFailures++
+	return c.consecFailures
+}
+
+// lookupBoth resolves A and AAAA via chain or OS. Per-family errors let
+// callers tell records, NODATA (nil err, no records), and failure apart.
+func (m *Resolver) lookupBoth(ctx context.Context, d domain.Domain, dnsName string) (aRecords, aaaaRecords []dns.RR, errA, errAAAA error) {
+	m.mutex.RLock()
+	chain := m.chain
+	maxPriority := m.chainMaxPriority
+	m.mutex.RUnlock()
+
+	if chain != nil && chain.HasRootHandlerAtOrBelow(maxPriority) {
+		aRecords, errA = m.lookupViaChain(ctx, chain, maxPriority, dnsName, dns.TypeA)
+		aaaaRecords, errAAAA = m.lookupViaChain(ctx, chain, maxPriority, dnsName, dns.TypeAAAA)
+		return
+	}
+
+	// TODO: drop once every supported OS registers a fallback resolver. Safe
+	// today: no root handler at priority ≤ PriorityUpstream means NetBird is
+	// not the system resolver, so net.DefaultResolver will not loop back.
+	aRecords, errA = m.osLookup(ctx, d, dnsName, dns.TypeA)
+	aaaaRecords, errAAAA = m.osLookup(ctx, d, dnsName, dns.TypeAAAA)
+	return
+}
+
+// lookupRecords resolves a single record type via chain or OS. The OS branch
+// arms the loop detector for the duration of its call so that ServeDNS can
+// spot the OS resolver routing the recursive query back to us.
+func (m *Resolver) lookupRecords(ctx context.Context, d domain.Domain, q dns.Question) ([]dns.RR, error) {
+	m.mutex.RLock()
+	chain := m.chain
+	maxPriority := m.chainMaxPriority
+	m.mutex.RUnlock()
+
+	if chain != nil && chain.HasRootHandlerAtOrBelow(maxPriority) {
+		return m.lookupViaChain(ctx, chain, maxPriority, q.Name, q.Qtype)
+	}
+
+	// TODO: drop once every supported OS registers a fallback resolver.
+	m.markRefreshing(q)
+	defer m.clearRefreshing(q)
+
+	return m.osLookup(ctx, d, q.Name, q.Qtype)
+}
+
+// lookupViaChain resolves via the handler chain and rewrites each RR to use
+// dnsName as owner and m.cacheTTL as TTL, so CNAME-backed domains don't cache
+// target-owned records or upstream TTLs. NODATA returns (nil, nil).
+func (m *Resolver) lookupViaChain(ctx context.Context, chain ChainResolver, maxPriority int, dnsName string, qtype uint16) ([]dns.RR, error) {
+	msg := &dns.Msg{}
+	msg.SetQuestion(dnsName, qtype)
+	msg.RecursionDesired = true
+
+	resp, err := chain.ResolveInternal(ctx, msg, maxPriority)
+	if err != nil {
+		return nil, fmt.Errorf("chain resolve: %w", err)
+	}
+	if resp == nil {
+		return nil, fmt.Errorf("chain resolve returned nil response")
+	}
+	if resp.Rcode != dns.RcodeSuccess {
+		return nil, fmt.Errorf("chain resolve rcode=%s", dns.RcodeToString[resp.Rcode])
+	}
+
+	ttl := uint32(m.cacheTTL.Seconds())
+	owners := cnameOwners(dnsName, resp.Answer)
+	var filtered []dns.RR
+	for _, rr := range resp.Answer {
+		h := rr.Header()
+		if h.Class != dns.ClassINET || h.Rrtype != qtype {
+			continue
+		}
+		if !owners[strings.ToLower(dns.Fqdn(h.Name))] {
+			continue
+		}
+		if cp := cloneIPRecord(rr, dnsName, ttl); cp != nil {
+			filtered = append(filtered, cp)
+		}
+	}
+	return filtered, nil
+}
+
+// osLookup resolves a single family via net.DefaultResolver using resutil,
+// which disambiguates NODATA from NXDOMAIN and Unmaps v4-mapped-v6. NODATA
+// returns (nil, nil).
+func (m *Resolver) osLookup(ctx context.Context, d domain.Domain, dnsName string, qtype uint16) ([]dns.RR, error) {
+	network := resutil.NetworkForQtype(qtype)
+	if network == "" {
+		return nil, fmt.Errorf("unsupported qtype %s", dns.TypeToString[qtype])
+	}
+
+	log.Infof("looking up IP for mgmt domain=%s type=%s", d.SafeString(), dns.TypeToString[qtype])
+	defer log.Infof("done looking up IP for mgmt domain=%s type=%s", d.SafeString(), dns.TypeToString[qtype])
+
+	result := resutil.LookupIP(ctx, net.DefaultResolver, network, d.PunycodeString(), qtype)
+	if result.Rcode == dns.RcodeSuccess {
+		return resutil.IPsToRRs(dnsName, result.IPs, uint32(m.cacheTTL.Seconds())), nil
+	}
+
+	if result.Err != nil {
+		return nil, fmt.Errorf("resolve %s type=%s: %w", d.SafeString(), dns.TypeToString[qtype], result.Err)
+	}
+	return nil, fmt.Errorf("resolve %s type=%s: rcode=%s", d.SafeString(), dns.TypeToString[qtype], dns.RcodeToString[result.Rcode])
+}
+
+// responseTTL returns the remaining cache lifetime in seconds (rounded up),
+// so downstream resolvers don't cache an answer for longer than we will.
+func (m *Resolver) responseTTL(cachedAt time.Time) uint32 {
+	remaining := m.cacheTTL - time.Since(cachedAt)
+	if remaining <= 0 {
+		return 0
+	}
+	return uint32((remaining + time.Second - 1) / time.Second)
 }
 
 // PopulateFromConfig extracts and caches domains from the client configuration.
@@ -224,19 +456,12 @@ func (m *Resolver) RemoveDomain(d domain.Domain) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
-	aQuestion := dns.Question{
-		Name:   dnsName,
-		Qtype:  dns.TypeA,
-		Qclass: dns.ClassINET,
-	}
-	delete(m.records, aQuestion)
-
-	aaaaQuestion := dns.Question{
-		Name:   dnsName,
-		Qtype:  dns.TypeAAAA,
-		Qclass: dns.ClassINET,
-	}
-	delete(m.records, aaaaQuestion)
+	qA := dns.Question{Name: dnsName, Qtype: dns.TypeA, Qclass: dns.ClassINET}
+	qAAAA := dns.Question{Name: dnsName, Qtype: dns.TypeAAAA, Qclass: dns.ClassINET}
+	delete(m.records, qA)
+	delete(m.records, qAAAA)
+	delete(m.refreshing, qA)
+	delete(m.refreshing, qAAAA)
 
 	log.Debugf("removed domain=%s from cache", d.SafeString())
 	return nil
@@ -394,3 +619,73 @@ func (m *Resolver) extractDomainsFromServerDomains(serverDomains dnsconfig.Serve
 
 	return domains
 }
+
+// cloneIPRecord returns a deep copy of rr retargeted to owner with ttl. Non
+// A/AAAA records return nil.
+func cloneIPRecord(rr dns.RR, owner string, ttl uint32) dns.RR {
+	switch r := rr.(type) {
+	case *dns.A:
+		cp := *r
+		cp.Hdr.Name = owner
+		cp.Hdr.Ttl = ttl
+		cp.A = slices.Clone(r.A)
+		return &cp
+	case *dns.AAAA:
+		cp := *r
+		cp.Hdr.Name = owner
+		cp.Hdr.Ttl = ttl
+		cp.AAAA = slices.Clone(r.AAAA)
+		return &cp
+	}
+	return nil
+}
+
+// cloneRecordsWithTTL clones A/AAAA records preserving their owner and
+// stamping ttl so the response shares no memory with the cached slice.
+func cloneRecordsWithTTL(records []dns.RR, ttl uint32) []dns.RR {
+	out := make([]dns.RR, 0, len(records))
+	for _, rr := range records {
+		if cp := cloneIPRecord(rr, rr.Header().Name, ttl); cp != nil {
+			out = append(out, cp)
+		}
+	}
+	return out
+}
+
+// cnameOwners returns dnsName plus every target reachable by following CNAMEs
+// in answer, iterating until fixed point so out-of-order chains resolve.
+func cnameOwners(dnsName string, answer []dns.RR) map[string]bool {
+	owners := map[string]bool{dnsName: true}
+	for {
+		added := false
+		for _, rr := range answer {
+			cname, ok := rr.(*dns.CNAME)
+			if !ok {
+				continue
+			}
+			name := strings.ToLower(dns.Fqdn(cname.Hdr.Name))
+			if !owners[name] {
+				continue
+			}
+			target := strings.ToLower(dns.Fqdn(cname.Target))
+			if !owners[target] {
+				owners[target] = true
+				added = true
+			}
+		}
+		if !added {
+			return owners
+		}
+	}
+}
+
+// resolveCacheTTL reads the cache TTL override env var; invalid or empty
+// values fall back to defaultTTL. Called once per Resolver from NewResolver.
+func resolveCacheTTL() time.Duration {
+	if v := os.Getenv(envMgmtCacheTTL); v != "" {
+		if d, err := time.ParseDuration(v); err == nil && d > 0 {
+			return d
+		}
+	}
+	return defaultTTL
+}

client/internal/dns/mgmt/mgmt_refresh_test.go

@@ -0,0 +1,408 @@
+package mgmt
+
+import (
+	"context"
+	"errors"
+	"net"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal/dns/test"
+	"github.com/netbirdio/netbird/shared/management/domain"
+)
+
+type fakeChain struct {
+	mu       sync.Mutex
+	calls    map[string]int
+	answers  map[string][]dns.RR
+	err      error
+	hasRoot  bool
+	onLookup func()
+}
+
+func newFakeChain() *fakeChain {
+	return &fakeChain{
+		calls:   map[string]int{},
+		answers: map[string][]dns.RR{},
+		hasRoot: true,
+	}
+}
+
+func (f *fakeChain) HasRootHandlerAtOrBelow(maxPriority int) bool {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return f.hasRoot
+}
+
+func (f *fakeChain) ResolveInternal(ctx context.Context, msg *dns.Msg, maxPriority int) (*dns.Msg, error) {
+	f.mu.Lock()
+	q := msg.Question[0]
+	key := q.Name + "|" + dns.TypeToString[q.Qtype]
+	f.calls[key]++
+	answers := f.answers[key]
+	err := f.err
+	onLookup := f.onLookup
+	f.mu.Unlock()
+
+	if onLookup != nil {
+		onLookup()
+	}
+	if err != nil {
+		return nil, err
+	}
+	resp := &dns.Msg{}
+	resp.SetReply(msg)
+	resp.Answer = answers
+	return resp, nil
+}
+
+func (f *fakeChain) setAnswer(name string, qtype uint16, ip string) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	key := name + "|" + dns.TypeToString[qtype]
+	hdr := dns.RR_Header{Name: name, Rrtype: qtype, Class: dns.ClassINET, Ttl: 60}
+	switch qtype {
+	case dns.TypeA:
+		f.answers[key] = []dns.RR{&dns.A{Hdr: hdr, A: net.ParseIP(ip).To4()}}
+	case dns.TypeAAAA:
+		f.answers[key] = []dns.RR{&dns.AAAA{Hdr: hdr, AAAA: net.ParseIP(ip).To16()}}
+	}
+}
+
+func (f *fakeChain) callCount(name string, qtype uint16) int {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return f.calls[name+"|"+dns.TypeToString[qtype]]
+}
+
+// waitFor polls the predicate until it returns true or the deadline passes.
+func waitFor(t *testing.T, d time.Duration, fn func() bool) {
+	t.Helper()
+	deadline := time.Now().Add(d)
+	for time.Now().Before(deadline) {
+		if fn() {
+			return
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	t.Fatalf("condition not met within %s", d)
+}
+
+func queryA(t *testing.T, r *Resolver, name string) *dns.Msg {
+	t.Helper()
+	msg := new(dns.Msg)
+	msg.SetQuestion(name, dns.TypeA)
+	w := &test.MockResponseWriter{}
+	r.ServeDNS(w, msg)
+	return w.GetLastResponse()
+}
+
+func firstA(t *testing.T, resp *dns.Msg) string {
+	t.Helper()
+	require.NotNil(t, resp)
+	require.Greater(t, len(resp.Answer), 0, "expected at least one answer")
+	a, ok := resp.Answer[0].(*dns.A)
+	require.True(t, ok, "expected A record")
+	return a.A.String()
+}
+
+func TestResolver_CacheTTLGatesRefresh(t *testing.T) {
+	// Same cached entry age, different cacheTTL values: the shorter TTL must
+	// trigger a background refresh, the longer one must not. Proves that the
+	// per-Resolver cacheTTL field actually drives the stale decision.
+	cachedAt := time.Now().Add(-100 * time.Millisecond)
+
+	newRec := func() *cachedRecord {
+		return &cachedRecord{
+			records: []dns.RR{&dns.A{
+				Hdr: dns.RR_Header{Name: "mgmt.example.com.", Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+				A:   net.ParseIP("10.0.0.1").To4(),
+			}},
+			cachedAt: cachedAt,
+		}
+	}
+	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
+
+	t.Run("short TTL treats entry as stale and refreshes", func(t *testing.T) {
+		r := NewResolver()
+		r.cacheTTL = 10 * time.Millisecond
+		chain := newFakeChain()
+		chain.setAnswer(q.Name, dns.TypeA, "10.0.0.2")
+		r.SetChainResolver(chain, 50)
+		r.records[q] = newRec()
+
+		resp := queryA(t, r, q.Name)
+		assert.Equal(t, "10.0.0.1", firstA(t, resp), "stale entry must be served while refresh runs")
+
+		waitFor(t, time.Second, func() bool {
+			return chain.callCount(q.Name, dns.TypeA) >= 1
+		})
+	})
+
+	t.Run("long TTL keeps entry fresh and skips refresh", func(t *testing.T) {
+		r := NewResolver()
+		r.cacheTTL = time.Hour
+		chain := newFakeChain()
+		chain.setAnswer(q.Name, dns.TypeA, "10.0.0.2")
+		r.SetChainResolver(chain, 50)
+		r.records[q] = newRec()
+
+		resp := queryA(t, r, q.Name)
+		assert.Equal(t, "10.0.0.1", firstA(t, resp))
+
+		time.Sleep(50 * time.Millisecond)
+		assert.Equal(t, 0, chain.callCount(q.Name, dns.TypeA), "fresh entry must not trigger refresh")
+	})
+}
+
+func TestResolver_ServeFresh_NoRefresh(t *testing.T) {
+	r := NewResolver()
+	chain := newFakeChain()
+	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
+	r.SetChainResolver(chain, 50)
+
+	r.records[dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}] = &cachedRecord{
+		records: []dns.RR{&dns.A{
+			Hdr: dns.RR_Header{Name: "mgmt.example.com.", Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+			A:   net.ParseIP("10.0.0.1").To4(),
+		}},
+		cachedAt: time.Now(), // fresh
+	}
+
+	resp := queryA(t, r, "mgmt.example.com.")
+	assert.Equal(t, "10.0.0.1", firstA(t, resp))
+
+	time.Sleep(20 * time.Millisecond)
+	assert.Equal(t, 0, chain.callCount("mgmt.example.com.", dns.TypeA), "fresh entry must not trigger refresh")
+}
+
+func TestResolver_StaleTriggersAsyncRefresh(t *testing.T) {
+	r := NewResolver()
+	chain := newFakeChain()
+	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
+	r.SetChainResolver(chain, 50)
+
+	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
+	r.records[q] = &cachedRecord{
+		records: []dns.RR{&dns.A{
+			Hdr: dns.RR_Header{Name: q.Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+			A:   net.ParseIP("10.0.0.1").To4(),
+		}},
+		cachedAt: time.Now().Add(-2 * defaultTTL), // stale
+	}
+
+	// First query: serves stale immediately.
+	resp := queryA(t, r, "mgmt.example.com.")
+	assert.Equal(t, "10.0.0.1", firstA(t, resp), "stale entry must be served while refresh runs")
+
+	waitFor(t, time.Second, func() bool {
+		return chain.callCount("mgmt.example.com.", dns.TypeA) >= 1
+	})
+
+	// Next query should now return the refreshed IP.
+	waitFor(t, time.Second, func() bool {
+		resp := queryA(t, r, "mgmt.example.com.")
+		return resp != nil && len(resp.Answer) > 0 && firstA(t, resp) == "10.0.0.2"
+	})
+}
+
+func TestResolver_ConcurrentStaleHitsCollapseRefresh(t *testing.T) {
+	r := NewResolver()
+	chain := newFakeChain()
+	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
+
+	var inflight atomic.Int32
+	var maxInflight atomic.Int32
+	chain.onLookup = func() {
+		cur := inflight.Add(1)
+		defer inflight.Add(-1)
+		for {
+			prev := maxInflight.Load()
+			if cur <= prev || maxInflight.CompareAndSwap(prev, cur) {
+				break
+			}
+		}
+		time.Sleep(50 * time.Millisecond) // hold inflight long enough to collide
+	}
+
+	r.SetChainResolver(chain, 50)
+
+	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
+	r.records[q] = &cachedRecord{
+		records: []dns.RR{&dns.A{
+			Hdr: dns.RR_Header{Name: q.Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+			A:   net.ParseIP("10.0.0.1").To4(),
+		}},
+		cachedAt: time.Now().Add(-2 * defaultTTL),
+	}
+
+	var wg sync.WaitGroup
+	for i := 0; i < 50; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			queryA(t, r, "mgmt.example.com.")
+		}()
+	}
+	wg.Wait()
+
+	waitFor(t, 2*time.Second, func() bool {
+		return inflight.Load() == 0
+	})
+
+	calls := chain.callCount("mgmt.example.com.", dns.TypeA)
+	assert.LessOrEqual(t, calls, 2, "singleflight must collapse concurrent refreshes (got %d)", calls)
+	assert.Equal(t, int32(1), maxInflight.Load(), "only one refresh should run concurrently")
+}
+
+func TestResolver_RefreshFailureArmsBackoff(t *testing.T) {
+	r := NewResolver()
+	chain := newFakeChain()
+	chain.err = errors.New("boom")
+	r.SetChainResolver(chain, 50)
+
+	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
+	r.records[q] = &cachedRecord{
+		records: []dns.RR{&dns.A{
+			Hdr: dns.RR_Header{Name: q.Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+			A:   net.ParseIP("10.0.0.1").To4(),
+		}},
+		cachedAt: time.Now().Add(-2 * defaultTTL),
+	}
+
+	// First stale hit triggers a refresh attempt that fails.
+	resp := queryA(t, r, "mgmt.example.com.")
+	assert.Equal(t, "10.0.0.1", firstA(t, resp), "stale entry served while refresh fails")
+
+	waitFor(t, time.Second, func() bool {
+		return chain.callCount("mgmt.example.com.", dns.TypeA) == 1
+	})
+	waitFor(t, time.Second, func() bool {
+		r.mutex.RLock()
+		defer r.mutex.RUnlock()
+		c, ok := r.records[q]
+		return ok && !c.lastFailedRefresh.IsZero()
+	})
+
+	// Subsequent stale hits within backoff window should not schedule more refreshes.
+	for i := 0; i < 10; i++ {
+		queryA(t, r, "mgmt.example.com.")
+	}
+	time.Sleep(50 * time.Millisecond)
+	assert.Equal(t, 1, chain.callCount("mgmt.example.com.", dns.TypeA), "backoff must suppress further refreshes")
+}
+
+func TestResolver_NoRootHandler_SkipsChain(t *testing.T) {
+	r := NewResolver()
+	chain := newFakeChain()
+	chain.hasRoot = false
+	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
+	r.SetChainResolver(chain, 50)
+
+	// With hasRoot=false the chain must not be consulted. Use a short
+	// deadline so the OS fallback returns quickly without waiting on a
+	// real network call in CI.
+	ctx, cancel := context.WithTimeout(context.Background(), 50*time.Millisecond)
+	defer cancel()
+	_, _, _, _ = r.lookupBoth(ctx, domain.Domain("mgmt.example.com"), "mgmt.example.com.")
+
+	assert.Equal(t, 0, chain.callCount("mgmt.example.com.", dns.TypeA),
+		"chain must not be used when no root handler is registered at the bound priority")
+}
+
+func TestResolver_ServeDuringRefreshSetsLoopFlag(t *testing.T) {
+	// ServeDNS being invoked for a question while a refresh for that question
+	// is inflight indicates a resolver loop (OS resolver sent the recursive
+	// query back to us). The inflightRefresh.loopLoggedOnce flag must be set.
+	r := NewResolver()
+
+	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
+	r.records[q] = &cachedRecord{
+		records: []dns.RR{&dns.A{
+			Hdr: dns.RR_Header{Name: q.Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+			A:   net.ParseIP("10.0.0.1").To4(),
+		}},
+		cachedAt: time.Now(),
+	}
+
+	// Simulate an inflight refresh.
+	r.markRefreshing(q)
+	defer r.clearRefreshing(q)
+
+	resp := queryA(t, r, "mgmt.example.com.")
+	assert.Equal(t, "10.0.0.1", firstA(t, resp), "stale entry must still be served to avoid breaking external queries")
+
+	r.mutex.RLock()
+	inflight := r.refreshing[q]
+	r.mutex.RUnlock()
+	require.NotNil(t, inflight)
+	assert.True(t, inflight.Load(), "loop flag must be set once a ServeDNS during refresh was observed")
+}
+
+func TestResolver_LoopFlagOnlyTrippedOncePerRefresh(t *testing.T) {
+	r := NewResolver()
+
+	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
+	r.records[q] = &cachedRecord{
+		records: []dns.RR{&dns.A{
+			Hdr: dns.RR_Header{Name: q.Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+			A:   net.ParseIP("10.0.0.1").To4(),
+		}},
+		cachedAt: time.Now(),
+	}
+
+	r.markRefreshing(q)
+	defer r.clearRefreshing(q)
+
+	// Multiple ServeDNS calls during the same refresh must not re-set the flag
+	// (CompareAndSwap from false -> true returns true only on the first call).
+	for range 5 {
+		queryA(t, r, "mgmt.example.com.")
+	}
+
+	r.mutex.RLock()
+	inflight := r.refreshing[q]
+	r.mutex.RUnlock()
+	assert.True(t, inflight.Load())
+}
+
+func TestResolver_NoLoopFlagWhenNotRefreshing(t *testing.T) {
+	r := NewResolver()
+
+	q := dns.Question{Name: "mgmt.example.com.", Qtype: dns.TypeA, Qclass: dns.ClassINET}
+	r.records[q] = &cachedRecord{
+		records: []dns.RR{&dns.A{
+			Hdr: dns.RR_Header{Name: q.Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+			A:   net.ParseIP("10.0.0.1").To4(),
+		}},
+		cachedAt: time.Now(),
+	}
+
+	queryA(t, r, "mgmt.example.com.")
+
+	r.mutex.RLock()
+	_, ok := r.refreshing[q]
+	r.mutex.RUnlock()
+	assert.False(t, ok, "no refresh inflight means no loop tracking")
+}
+
+func TestResolver_AddDomain_UsesChainWhenRootRegistered(t *testing.T) {
+	r := NewResolver()
+	chain := newFakeChain()
+	chain.setAnswer("mgmt.example.com.", dns.TypeA, "10.0.0.2")
+	chain.setAnswer("mgmt.example.com.", dns.TypeAAAA, "fd00::2")
+	r.SetChainResolver(chain, 50)
+
+	require.NoError(t, r.AddDomain(context.Background(), domain.Domain("mgmt.example.com")))
+
+	resp := queryA(t, r, "mgmt.example.com.")
+	assert.Equal(t, "10.0.0.2", firstA(t, resp))
+	assert.Equal(t, 1, chain.callCount("mgmt.example.com.", dns.TypeA))
+	assert.Equal(t, 1, chain.callCount("mgmt.example.com.", dns.TypeAAAA))
+}

client/internal/dns/mgmt/mgmt_test.go

@@ -6,6 +6,7 @@ import (
 	"net/url"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/miekg/dns"
 	"github.com/stretchr/testify/assert"
@@ -23,6 +24,60 @@ func TestResolver_NewResolver(t *testing.T) {
 	assert.False(t, resolver.MatchSubdomains())
 }
 
+func TestResolveCacheTTL(t *testing.T) {
+	tests := []struct {
+		name  string
+		value string
+		want  time.Duration
+	}{
+		{"unset falls back to default", "", defaultTTL},
+		{"valid duration", "45s", 45 * time.Second},
+		{"valid minutes", "2m", 2 * time.Minute},
+		{"malformed falls back to default", "not-a-duration", defaultTTL},
+		{"zero falls back to default", "0s", defaultTTL},
+		{"negative falls back to default", "-5s", defaultTTL},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Setenv(envMgmtCacheTTL, tc.value)
+			got := resolveCacheTTL()
+			assert.Equal(t, tc.want, got, "parsed TTL should match")
+		})
+	}
+}
+
+func TestNewResolver_CacheTTLFromEnv(t *testing.T) {
+	t.Setenv(envMgmtCacheTTL, "7s")
+	r := NewResolver()
+	assert.Equal(t, 7*time.Second, r.cacheTTL, "NewResolver should evaluate cacheTTL once from env")
+}
+
+func TestResolver_ResponseTTL(t *testing.T) {
+	now := time.Now()
+	tests := []struct {
+		name     string
+		cacheTTL time.Duration
+		cachedAt time.Time
+		wantMin  uint32
+		wantMax  uint32
+	}{
+		{"fresh entry returns full TTL", 60 * time.Second, now, 59, 60},
+		{"half-aged entry returns half TTL", 60 * time.Second, now.Add(-30 * time.Second), 29, 31},
+		{"expired entry returns zero", 60 * time.Second, now.Add(-61 * time.Second), 0, 0},
+		{"exactly expired returns zero", 10 * time.Second, now.Add(-10 * time.Second), 0, 0},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			r := &Resolver{cacheTTL: tc.cacheTTL}
+			got := r.responseTTL(tc.cachedAt)
+			assert.GreaterOrEqual(t, got, tc.wantMin, "remaining TTL should be >= wantMin")
+			assert.LessOrEqual(t, got, tc.wantMax, "remaining TTL should be <= wantMax")
+		})
+	}
+}
+
 func TestResolver_ExtractDomainFromURL(t *testing.T) {
 	tests := []struct {
 		name        string

client/internal/dns/mock_server.go

@@ -90,6 +90,11 @@ func (m *MockServer) SetRouteChecker(func(netip.Addr) bool) {
 	// Mock implementation - no-op
 }
 
+// SetFirewall mock implementation of SetFirewall from Server interface
+func (m *MockServer) SetFirewall(Firewall) {
+	// Mock implementation - no-op
+}
+
 // BeginBatch mock implementation of BeginBatch from Server interface
 func (m *MockServer) BeginBatch() {
 	// Mock implementation - no-op

client/internal/dns/response_writer.go

@@ -104,3 +104,23 @@ func (r *responseWriter) TsigTimersOnly(bool) {
 // After a call to Hijack(), the DNS package will not do anything with the connection.
 func (r *responseWriter) Hijack() {
 }
+
+// remoteAddrFromPacket extracts the source IP:port from a decoded packet for logging.
+func remoteAddrFromPacket(packet gopacket.Packet) *net.UDPAddr {
+	var srcIP net.IP
+	if ipv4 := packet.Layer(layers.LayerTypeIPv4); ipv4 != nil {
+		srcIP = ipv4.(*layers.IPv4).SrcIP
+	} else if ipv6 := packet.Layer(layers.LayerTypeIPv6); ipv6 != nil {
+		srcIP = ipv6.(*layers.IPv6).SrcIP
+	}
+
+	var srcPort int
+	if udp := packet.Layer(layers.LayerTypeUDP); udp != nil {
+		srcPort = int(udp.(*layers.UDP).SrcPort)
+	}
+
+	if srcIP == nil {
+		return nil
+	}
+	return &net.UDPAddr{IP: srcIP, Port: srcPort}
+}

client/internal/dns/server.go

@@ -58,6 +58,7 @@ type Server interface {
 	UpdateServerConfig(domains dnsconfig.ServerDomains) error
 	PopulateManagementDomain(mgmtURL *url.URL) error
 	SetRouteChecker(func(netip.Addr) bool)
+	SetFirewall(Firewall)
 }
 
 type nsGroupsByDomain struct {
@@ -151,7 +152,7 @@ func NewDefaultServer(ctx context.Context, config DefaultServerConfig) (*Default
 	if config.WgInterface.IsUserspaceBind() {
 		dnsService = NewServiceViaMemory(config.WgInterface)
 	} else {
-		dnsService = newServiceViaListener(config.WgInterface, addrPort)
+		dnsService = newServiceViaListener(config.WgInterface, addrPort, nil)
 	}
 
 	server := newDefaultServer(ctx, config.WgInterface, dnsService, config.StatusRecorder, config.StateManager, config.DisableSys)
@@ -186,11 +187,16 @@ func NewDefaultServerIos(
 	ctx context.Context,
 	wgInterface WGIface,
 	iosDnsManager IosDnsManager,
+	hostsDnsList []netip.AddrPort,
 	statusRecorder *peer.Status,
 	disableSys bool,
 ) *DefaultServer {
+	log.Debugf("iOS host dns address list is: %v", hostsDnsList)
 	ds := newDefaultServer(ctx, wgInterface, NewServiceViaMemory(wgInterface), statusRecorder, nil, disableSys)
 	ds.iosDnsManager = iosDnsManager
+	ds.hostsDNSHolder.set(hostsDnsList)
+	ds.permanent = true
+	ds.addHostRootZone()
 	return ds
 }
 
@@ -206,6 +212,7 @@ func newDefaultServer(
 	ctx, stop := context.WithCancel(ctx)
 
 	mgmtCacheResolver := mgmt.NewResolver()
+	mgmtCacheResolver.SetChainResolver(handlerChain, PriorityUpstream)
 
 	defaultServer := &DefaultServer{
 		ctx:               ctx,
@@ -374,6 +381,17 @@ func (s *DefaultServer) DnsIP() netip.Addr {
 	return s.service.RuntimeIP()
 }
 
+// SetFirewall sets the firewall used for DNS port DNAT rules.
+// This must be called before Initialize when using the listener-based service,
+// because the firewall is typically not available at construction time.
+func (s *DefaultServer) SetFirewall(fw Firewall) {
+	if svc, ok := s.service.(*serviceViaListener); ok {
+		svc.listenerFlagLock.Lock()
+		svc.firewall = fw
+		svc.listenerFlagLock.Unlock()
+	}
+}
+
 // Stop stops the server
 func (s *DefaultServer) Stop() {
 	s.probeMu.Lock()
@@ -395,8 +413,12 @@ func (s *DefaultServer) Stop() {
 	maps.Clear(s.extraDomains)
 }
 
-func (s *DefaultServer) disableDNS() error {
-	defer s.service.Stop()
+func (s *DefaultServer) disableDNS() (retErr error) {
+	defer func() {
+		if err := s.service.Stop(); err != nil {
+			retErr = errors.Join(retErr, fmt.Errorf("stop DNS service: %w", err))
+		}
+	}()
 
 	if s.isUsingNoopHostManager() {
 		return nil

client/internal/dns/server_test.go

@@ -476,8 +476,8 @@ func TestDNSFakeResolverHandleUpdates(t *testing.T) {
 
 	packetfilter := pfmock.NewMockPacketFilter(ctrl)
 	packetfilter.EXPECT().FilterOutbound(gomock.Any(), gomock.Any()).AnyTimes()
-	packetfilter.EXPECT().AddUDPPacketHook(gomock.Any(), gomock.Any(), gomock.Any(), gomock.Any())
-	packetfilter.EXPECT().RemovePacketHook(gomock.Any())
+	packetfilter.EXPECT().SetUDPPacketHook(gomock.Any(), gomock.Any(), gomock.Any()).AnyTimes()
+	packetfilter.EXPECT().SetTCPPacketHook(gomock.Any(), gomock.Any(), gomock.Any()).AnyTimes()
 
 	if err := wgIface.SetFilter(packetfilter); err != nil {
 		t.Errorf("set packet filter: %v", err)
@@ -1071,7 +1071,7 @@ func (m *mockHandler) ID() types.HandlerID                   { return types.Hand
 type mockService struct{}
 
 func (m *mockService) Listen() error                   { return nil }
-func (m *mockService) Stop()                           {}
+func (m *mockService) Stop() error                     { return nil }
 func (m *mockService) RuntimeIP() netip.Addr           { return netip.MustParseAddr("127.0.0.1") }
 func (m *mockService) RuntimePort() int                { return 53 }
 func (m *mockService) RegisterMux(string, dns.Handler) {}

client/internal/dns/service.go

@@ -4,15 +4,25 @@ import (
 	"net/netip"
 
 	"github.com/miekg/dns"
+
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 )
 
 const (
 	DefaultPort = 53
 )
 
+// Firewall provides DNAT capabilities for DNS port redirection.
+// This is used when the DNS server cannot bind port 53 directly
+// and needs firewall rules to redirect traffic.
+type Firewall interface {
+	AddOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error
+	RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, sourcePort, targetPort uint16) error
+}
+
 type service interface {
 	Listen() error
-	Stop()
+	Stop() error
 	RegisterMux(domain string, handler dns.Handler)
 	DeregisterMux(key string)
 	RuntimePort() int

client/internal/dns/service_listener.go

@@ -10,9 +10,13 @@ import (
 	"sync"
 	"time"
 
+	"github.com/hashicorp/go-multierror"
 	"github.com/miekg/dns"
 	log "github.com/sirupsen/logrus"
 
+	nberrors "github.com/netbirdio/netbird/client/errors"
+
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
 	"github.com/netbirdio/netbird/client/internal/ebpf"
 	ebpfMgr "github.com/netbirdio/netbird/client/internal/ebpf/manager"
 )
@@ -31,25 +35,33 @@ type serviceViaListener struct {
 	dnsMux            *dns.ServeMux
 	customAddr        *netip.AddrPort
 	server            *dns.Server
+	tcpServer         *dns.Server
 	listenIP          netip.Addr
 	listenPort        uint16
 	listenerIsRunning bool
 	listenerFlagLock  sync.Mutex
 	ebpfService       ebpfMgr.Manager
+	firewall          Firewall
+	tcpDNATConfigured bool
 }
 
-func newServiceViaListener(wgIface WGIface, customAddr *netip.AddrPort) *serviceViaListener {
+func newServiceViaListener(wgIface WGIface, customAddr *netip.AddrPort, fw Firewall) *serviceViaListener {
 	mux := dns.NewServeMux()
 
 	s := &serviceViaListener{
 		wgInterface: wgIface,
 		dnsMux:      mux,
 		customAddr:  customAddr,
+		firewall:    fw,
 		server: &dns.Server{
 			Net:     "udp",
 			Handler: mux,
 			UDPSize: 65535,
 		},
+		tcpServer: &dns.Server{
+			Net:     "tcp",
+			Handler: mux,
+		},
 	}
 
 	return s
@@ -70,43 +82,86 @@ func (s *serviceViaListener) Listen() error {
 		return fmt.Errorf("eval listen address: %w", err)
 	}
 	s.listenIP = s.listenIP.Unmap()
-	s.server.Addr = net.JoinHostPort(s.listenIP.String(), strconv.Itoa(int(s.listenPort)))
-	log.Debugf("starting dns on %s", s.server.Addr)
-	go func() {
-		s.setListenerStatus(true)
-		defer s.setListenerStatus(false)
+	addr := net.JoinHostPort(s.listenIP.String(), strconv.Itoa(int(s.listenPort)))
+	s.server.Addr = addr
+	s.tcpServer.Addr = addr
 
-		err := s.server.ListenAndServe()
-		if err != nil {
-			log.Errorf("dns server running with %d port returned an error: %v. Will not retry", s.listenPort, err)
+	log.Debugf("starting dns on %s (UDP + TCP)", addr)
+	s.listenerIsRunning = true
+
+	go func() {
+		if err := s.server.ListenAndServe(); err != nil {
+			log.Errorf("failed to run DNS UDP server on port %d: %v", s.listenPort, err)
+		}
+
+		s.listenerFlagLock.Lock()
+		unexpected := s.listenerIsRunning
+		s.listenerIsRunning = false
+		s.listenerFlagLock.Unlock()
+
+		if unexpected {
+			if err := s.tcpServer.Shutdown(); err != nil {
+				log.Debugf("failed to shutdown DNS TCP server: %v", err)
+			}
 		}
 	}()
 
+	go func() {
+		if err := s.tcpServer.ListenAndServe(); err != nil {
+			log.Errorf("failed to run DNS TCP server on port %d: %v", s.listenPort, err)
+		}
+	}()
+
+	// When eBPF redirects UDP port 53 to our listen port, TCP still needs
+	// a DNAT rule because eBPF only handles UDP.
+	if s.ebpfService != nil && s.firewall != nil && s.listenPort != DefaultPort {
+		if err := s.firewall.AddOutputDNAT(s.listenIP, firewall.ProtocolTCP, DefaultPort, s.listenPort); err != nil {
+			log.Warnf("failed to add DNS TCP DNAT rule, TCP DNS on port 53 will not work: %v", err)
+		} else {
+			s.tcpDNATConfigured = true
+			log.Infof("added DNS TCP DNAT rule: %s:%d -> %s:%d", s.listenIP, DefaultPort, s.listenIP, s.listenPort)
+		}
+	}
+
 	return nil
 }
 
-func (s *serviceViaListener) Stop() {
+func (s *serviceViaListener) Stop() error {
 	s.listenerFlagLock.Lock()
 	defer s.listenerFlagLock.Unlock()
 
 	if !s.listenerIsRunning {
-		return
+		return nil
 	}
+	s.listenerIsRunning = false
 
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
-	err := s.server.ShutdownContext(ctx)
-	if err != nil {
-		log.Errorf("stopping dns server listener returned an error: %v", err)
+	var merr *multierror.Error
+
+	if err := s.server.ShutdownContext(ctx); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("stop DNS UDP server: %w", err))
+	}
+
+	if err := s.tcpServer.ShutdownContext(ctx); err != nil {
+		merr = multierror.Append(merr, fmt.Errorf("stop DNS TCP server: %w", err))
+	}
+
+	if s.tcpDNATConfigured && s.firewall != nil {
+		if err := s.firewall.RemoveOutputDNAT(s.listenIP, firewall.ProtocolTCP, DefaultPort, s.listenPort); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("remove DNS TCP DNAT rule: %w", err))
+		}
+		s.tcpDNATConfigured = false
 	}
 
 	if s.ebpfService != nil {
-		err = s.ebpfService.FreeDNSFwd()
-		if err != nil {
-			log.Errorf("stopping traffic forwarder returned an error: %v", err)
+		if err := s.ebpfService.FreeDNSFwd(); err != nil {
+			merr = multierror.Append(merr, fmt.Errorf("stop traffic forwarder: %w", err))
 		}
 	}
+
+	return nberrors.FormatErrorOrNil(merr)
 }
 
 func (s *serviceViaListener) RegisterMux(pattern string, handler dns.Handler) {
@@ -133,12 +188,6 @@ func (s *serviceViaListener) RuntimeIP() netip.Addr {
 	return s.listenIP
 }
 
-func (s *serviceViaListener) setListenerStatus(running bool) {
-	s.listenerFlagLock.Lock()
-	defer s.listenerFlagLock.Unlock()
-
-	s.listenerIsRunning = running
-}
 
 // evalListenAddress figure out the listen address for the DNS server
 // first check the 53 port availability on WG interface or lo, if not success
@@ -187,18 +236,28 @@ func (s *serviceViaListener) testFreePort(port int) (netip.Addr, bool) {
 }
 
 func (s *serviceViaListener) tryToBind(ip netip.Addr, port int) bool {
-	addrString := net.JoinHostPort(ip.String(), strconv.Itoa(port))
-	udpAddr := net.UDPAddrFromAddrPort(netip.MustParseAddrPort(addrString))
-	probeListener, err := net.ListenUDP("udp", udpAddr)
+	addrPort := netip.AddrPortFrom(ip, uint16(port))
+
+	udpAddr := net.UDPAddrFromAddrPort(addrPort)
+	udpLn, err := net.ListenUDP("udp", udpAddr)
 	if err != nil {
-		log.Warnf("binding dns on %s is not available, error: %s", addrString, err)
+		log.Warnf("binding dns UDP on %s is not available: %s", addrPort, err)
 		return false
 	}
-
-	err = probeListener.Close()
-	if err != nil {
-		log.Errorf("got an error closing the probe listener, error: %s", err)
+	if err := udpLn.Close(); err != nil {
+		log.Debugf("close UDP probe listener: %s", err)
 	}
+
+	tcpAddr := net.TCPAddrFromAddrPort(addrPort)
+	tcpLn, err := net.ListenTCP("tcp", tcpAddr)
+	if err != nil {
+		log.Warnf("binding dns TCP on %s is not available: %s", addrPort, err)
+		return false
+	}
+	if err := tcpLn.Close(); err != nil {
+		log.Debugf("close TCP probe listener: %s", err)
+	}
+
 	return true
 }
 

client/internal/dns/service_listener_test.go

@@ -0,0 +1,86 @@
+package dns
+
+import (
+	"fmt"
+	"net"
+	"net/netip"
+	"testing"
+	"time"
+
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestServiceViaListener_TCPAndUDP(t *testing.T) {
+	handler := dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
+		m := new(dns.Msg)
+		m.SetReply(r)
+		m.Answer = append(m.Answer, &dns.A{
+			Hdr: dns.RR_Header{Name: r.Question[0].Name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 60},
+			A:   net.ParseIP("192.0.2.1"),
+		})
+		if err := w.WriteMsg(m); err != nil {
+			t.Logf("write msg: %v", err)
+		}
+	})
+
+	// Create a service using a custom address to avoid needing root
+	svc := newServiceViaListener(nil, nil, nil)
+	svc.dnsMux.Handle(".", handler)
+
+	// Bind both transports up front to avoid TOCTOU races.
+	udpAddr := net.UDPAddrFromAddrPort(netip.AddrPortFrom(customIP, 0))
+	udpConn, err := net.ListenUDP("udp", udpAddr)
+	if err != nil {
+		t.Skip("cannot bind to 127.0.0.153, skipping")
+	}
+	port := uint16(udpConn.LocalAddr().(*net.UDPAddr).Port)
+
+	tcpAddr := net.TCPAddrFromAddrPort(netip.AddrPortFrom(customIP, port))
+	tcpLn, err := net.ListenTCP("tcp", tcpAddr)
+	if err != nil {
+		udpConn.Close()
+		t.Skip("cannot bind TCP on same port, skipping")
+	}
+
+	addr := fmt.Sprintf("%s:%d", customIP, port)
+	svc.server.PacketConn = udpConn
+	svc.tcpServer.Listener = tcpLn
+	svc.listenIP = customIP
+	svc.listenPort = port
+
+	go func() {
+		if err := svc.server.ActivateAndServe(); err != nil {
+			t.Logf("udp server: %v", err)
+		}
+	}()
+	go func() {
+		if err := svc.tcpServer.ActivateAndServe(); err != nil {
+			t.Logf("tcp server: %v", err)
+		}
+	}()
+	svc.listenerIsRunning = true
+
+	defer func() {
+		require.NoError(t, svc.Stop())
+	}()
+
+	q := new(dns.Msg).SetQuestion("example.com.", dns.TypeA)
+
+	// Test UDP query
+	udpClient := &dns.Client{Net: "udp", Timeout: 2 * time.Second}
+	udpResp, _, err := udpClient.Exchange(q, addr)
+	require.NoError(t, err, "UDP query should succeed")
+	require.NotNil(t, udpResp)
+	require.NotEmpty(t, udpResp.Answer)
+	assert.Contains(t, udpResp.Answer[0].String(), "192.0.2.1", "UDP response should contain expected IP")
+
+	// Test TCP query
+	tcpClient := &dns.Client{Net: "tcp", Timeout: 2 * time.Second}
+	tcpResp, _, err := tcpClient.Exchange(q, addr)
+	require.NoError(t, err, "TCP query should succeed")
+	require.NotNil(t, tcpResp)
+	require.NotEmpty(t, tcpResp.Answer)
+	assert.Contains(t, tcpResp.Answer[0].String(), "192.0.2.1", "TCP response should contain expected IP")
+}

client/internal/dns/service_memory.go

@@ -1,6 +1,7 @@
 package dns
 
 import (
+	"errors"
 	"fmt"
 	"net/netip"
 	"sync"
@@ -10,6 +11,7 @@ import (
 	"github.com/miekg/dns"
 	log "github.com/sirupsen/logrus"
 
+	"github.com/netbirdio/netbird/client/iface"
 	nbnet "github.com/netbirdio/netbird/client/net"
 )
 
@@ -18,7 +20,8 @@ type ServiceViaMemory struct {
 	dnsMux            *dns.ServeMux
 	runtimeIP         netip.Addr
 	runtimePort       int
-	udpFilterHookID   string
+	tcpDNS            *tcpDNSServer
+	tcpHookSet        bool
 	listenerIsRunning bool
 	listenerFlagLock  sync.Mutex
 }
@@ -28,14 +31,13 @@ func NewServiceViaMemory(wgIface WGIface) *ServiceViaMemory {
 	if err != nil {
 		log.Errorf("get last ip from network: %v", err)
 	}
-	s := &ServiceViaMemory{
+
+	return &ServiceViaMemory{
 		wgInterface: wgIface,
 		dnsMux:      dns.NewServeMux(),
-
 		runtimeIP:   lastIP,
 		runtimePort: DefaultPort,
 	}
-	return s
 }
 
 func (s *ServiceViaMemory) Listen() error {
@@ -46,10 +48,8 @@ func (s *ServiceViaMemory) Listen() error {
 		return nil
 	}
 
-	var err error
-	s.udpFilterHookID, err = s.filterDNSTraffic()
-	if err != nil {
-		return fmt.Errorf("filter dns traffice: %w", err)
+	if err := s.filterDNSTraffic(); err != nil {
+		return fmt.Errorf("filter dns traffic: %w", err)
 	}
 	s.listenerIsRunning = true
 
@@ -57,19 +57,29 @@ func (s *ServiceViaMemory) Listen() error {
 	return nil
 }
 
-func (s *ServiceViaMemory) Stop() {
+func (s *ServiceViaMemory) Stop() error {
 	s.listenerFlagLock.Lock()
 	defer s.listenerFlagLock.Unlock()
 
 	if !s.listenerIsRunning {
-		return
+		return nil
 	}
 
-	if err := s.wgInterface.GetFilter().RemovePacketHook(s.udpFilterHookID); err != nil {
-		log.Errorf("unable to remove DNS packet hook: %s", err)
+	filter := s.wgInterface.GetFilter()
+	if filter != nil {
+		filter.SetUDPPacketHook(s.runtimeIP, uint16(s.runtimePort), nil)
+		if s.tcpHookSet {
+			filter.SetTCPPacketHook(s.runtimeIP, uint16(s.runtimePort), nil)
+		}
+	}
+
+	if s.tcpDNS != nil {
+		s.tcpDNS.Stop()
 	}
 
 	s.listenerIsRunning = false
+
+	return nil
 }
 
 func (s *ServiceViaMemory) RegisterMux(pattern string, handler dns.Handler) {
@@ -88,10 +98,18 @@ func (s *ServiceViaMemory) RuntimeIP() netip.Addr {
 	return s.runtimeIP
 }
 
-func (s *ServiceViaMemory) filterDNSTraffic() (string, error) {
+func (s *ServiceViaMemory) filterDNSTraffic() error {
 	filter := s.wgInterface.GetFilter()
 	if filter == nil {
-		return "", fmt.Errorf("can't set DNS filter, filter not initialized")
+		return errors.New("DNS filter not initialized")
+	}
+
+	// Create TCP DNS server lazily here since the device may not exist at construction time.
+	if s.tcpDNS == nil {
+		if dev := s.wgInterface.GetDevice(); dev != nil {
+			// MTU only affects TCP segment sizing; DNS messages are small so this has no practical impact.
+			s.tcpDNS = newTCPDNSServer(s.dnsMux, dev.Device, s.runtimeIP, uint16(s.runtimePort), iface.DefaultMTU)
+		}
 	}
 
 	firstLayerDecoder := layers.LayerTypeIPv4
@@ -100,12 +118,16 @@ func (s *ServiceViaMemory) filterDNSTraffic() (string, error) {
 	}
 
 	hook := func(packetData []byte) bool {
-		// Decode the packet
 		packet := gopacket.NewPacket(packetData, firstLayerDecoder, gopacket.Default)
 
-		// Get the UDP layer
 		udpLayer := packet.Layer(layers.LayerTypeUDP)
-		udp := udpLayer.(*layers.UDP)
+		if udpLayer == nil {
+			return true
+		}
+		udp, ok := udpLayer.(*layers.UDP)
+		if !ok {
+			return true
+		}
 
 		msg := new(dns.Msg)
 		if err := msg.Unpack(udp.Payload); err != nil {
@@ -113,13 +135,30 @@ func (s *ServiceViaMemory) filterDNSTraffic() (string, error) {
 			return true
 		}
 
-		writer := responseWriter{
-			packet: packet,
-			device: s.wgInterface.GetDevice().Device,
+		dev := s.wgInterface.GetDevice()
+		if dev == nil {
+			return true
 		}
-		go s.dnsMux.ServeDNS(&writer, msg)
+
+		writer := &responseWriter{
+			remote: remoteAddrFromPacket(packet),
+			packet: packet,
+			device: dev.Device,
+		}
+		go s.dnsMux.ServeDNS(writer, msg)
 		return true
 	}
 
-	return filter.AddUDPPacketHook(false, s.runtimeIP, uint16(s.runtimePort), hook), nil
+	filter.SetUDPPacketHook(s.runtimeIP, uint16(s.runtimePort), hook)
+
+	if s.tcpDNS != nil {
+		tcpHook := func(packetData []byte) bool {
+			s.tcpDNS.InjectPacket(packetData)
+			return true
+		}
+		filter.SetTCPPacketHook(s.runtimeIP, uint16(s.runtimePort), tcpHook)
+		s.tcpHookSet = true
+	}
+
+	return nil
 }

client/internal/dns/tcpstack.go

@@ -0,0 +1,444 @@
+package dns
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/netip"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/miekg/dns"
+	log "github.com/sirupsen/logrus"
+	"golang.zx2c4.com/wireguard/tun"
+	"gvisor.dev/gvisor/pkg/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.dev/gvisor/pkg/waiter"
+)
+
+const (
+	dnsTCPReceiveWindow = 8192
+	dnsTCPMaxInFlight   = 16
+	dnsTCPIdleTimeout   = 30 * time.Second
+	dnsTCPReadTimeout   = 5 * time.Second
+)
+
+// tcpDNSServer is an on-demand TCP DNS server backed by a minimal gvisor stack.
+// It is started lazily when a truncated DNS response is detected and shuts down
+// after a period of inactivity to conserve resources.
+type tcpDNSServer struct {
+	mu     sync.Mutex
+	s      *stack.Stack
+	ep     *dnsEndpoint
+	mux    *dns.ServeMux
+	tunDev tun.Device
+	ip     netip.Addr
+	port   uint16
+	mtu    uint16
+
+	running bool
+	closed  bool
+	timerID uint64
+	timer   *time.Timer
+}
+
+func newTCPDNSServer(mux *dns.ServeMux, tunDev tun.Device, ip netip.Addr, port uint16, mtu uint16) *tcpDNSServer {
+	return &tcpDNSServer{
+		mux:    mux,
+		tunDev: tunDev,
+		ip:     ip,
+		port:   port,
+		mtu:    mtu,
+	}
+}
+
+// InjectPacket ensures the stack is running and delivers a raw IP packet into
+// the gvisor stack for TCP processing. Combining both operations under a single
+// lock prevents a race where the idle timer could stop the stack between
+// start and delivery.
+func (t *tcpDNSServer) InjectPacket(payload []byte) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	if t.closed {
+		return
+	}
+
+	if !t.running {
+		if err := t.startLocked(); err != nil {
+			log.Errorf("failed to start TCP DNS stack: %v", err)
+			return
+		}
+		t.running = true
+		log.Debugf("TCP DNS stack started on %s:%d (triggered by %s)", t.ip, t.port, srcAddrFromPacket(payload))
+	}
+	t.resetTimerLocked()
+
+	ep := t.ep
+	if ep == nil || ep.dispatcher == nil {
+		return
+	}
+
+	pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
+		Payload: buffer.MakeWithData(payload),
+	})
+	// DeliverNetworkPacket takes ownership of the packet buffer; do not DecRef.
+	ep.dispatcher.DeliverNetworkPacket(ipv4.ProtocolNumber, pkt)
+}
+
+// Stop tears down the gvisor stack and releases resources permanently.
+// After Stop, InjectPacket becomes a no-op.
+func (t *tcpDNSServer) Stop() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	t.stopLocked()
+	t.closed = true
+}
+
+func (t *tcpDNSServer) startLocked() error {
+	// TODO: add ipv6.NewProtocol when IPv6 overlay support lands.
+	s := stack.New(stack.Options{
+		NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol},
+		TransportProtocols: []stack.TransportProtocolFactory{tcp.NewProtocol},
+		HandleLocal:        false,
+	})
+
+	nicID := tcpip.NICID(1)
+	ep := &dnsEndpoint{
+		tunDev: t.tunDev,
+	}
+	ep.mtu.Store(uint32(t.mtu))
+
+	if err := s.CreateNIC(nicID, ep); err != nil {
+		s.Close()
+		s.Wait()
+		return fmt.Errorf("create NIC: %v", err)
+	}
+
+	protoAddr := tcpip.ProtocolAddress{
+		Protocol: ipv4.ProtocolNumber,
+		AddressWithPrefix: tcpip.AddressWithPrefix{
+			Address:   tcpip.AddrFromSlice(t.ip.AsSlice()),
+			PrefixLen: 32,
+		},
+	}
+	if err := s.AddProtocolAddress(nicID, protoAddr, stack.AddressProperties{}); err != nil {
+		s.Close()
+		s.Wait()
+		return fmt.Errorf("add protocol address: %s", err)
+	}
+
+	if err := s.SetPromiscuousMode(nicID, true); err != nil {
+		s.Close()
+		s.Wait()
+		return fmt.Errorf("set promiscuous mode: %s", err)
+	}
+	if err := s.SetSpoofing(nicID, true); err != nil {
+		s.Close()
+		s.Wait()
+		return fmt.Errorf("set spoofing: %s", err)
+	}
+
+	defaultSubnet, err := tcpip.NewSubnet(
+		tcpip.AddrFrom4([4]byte{0, 0, 0, 0}),
+		tcpip.MaskFromBytes([]byte{0, 0, 0, 0}),
+	)
+	if err != nil {
+		s.Close()
+		s.Wait()
+		return fmt.Errorf("create default subnet: %w", err)
+	}
+
+	s.SetRouteTable([]tcpip.Route{
+		{Destination: defaultSubnet, NIC: nicID},
+	})
+
+	tcpFwd := tcp.NewForwarder(s, dnsTCPReceiveWindow, dnsTCPMaxInFlight, func(r *tcp.ForwarderRequest) {
+		t.handleTCPDNS(r)
+	})
+	s.SetTransportProtocolHandler(tcp.ProtocolNumber, tcpFwd.HandlePacket)
+
+	t.s = s
+	t.ep = ep
+	return nil
+}
+
+func (t *tcpDNSServer) stopLocked() {
+	if !t.running {
+		return
+	}
+
+	if t.timer != nil {
+		t.timer.Stop()
+		t.timer = nil
+	}
+
+	if t.s != nil {
+		t.s.Close()
+		t.s.Wait()
+		t.s = nil
+	}
+	t.ep = nil
+	t.running = false
+
+	log.Debugf("TCP DNS stack stopped")
+}
+
+func (t *tcpDNSServer) resetTimerLocked() {
+	if t.timer != nil {
+		t.timer.Stop()
+	}
+	t.timerID++
+	id := t.timerID
+	t.timer = time.AfterFunc(dnsTCPIdleTimeout, func() {
+		t.mu.Lock()
+		defer t.mu.Unlock()
+
+		// Only stop if this timer is still the active one.
+		// A racing InjectPacket may have replaced it.
+		if t.timerID != id {
+			return
+		}
+		t.stopLocked()
+	})
+}
+
+func (t *tcpDNSServer) handleTCPDNS(r *tcp.ForwarderRequest) {
+	id := r.ID()
+
+	wq := waiter.Queue{}
+	ep, epErr := r.CreateEndpoint(&wq)
+	if epErr != nil {
+		log.Debugf("TCP DNS: failed to create endpoint: %v", epErr)
+		r.Complete(true)
+		return
+	}
+	r.Complete(false)
+
+	conn := gonet.NewTCPConn(&wq, ep)
+	defer func() {
+		if err := conn.Close(); err != nil {
+			log.Tracef("TCP DNS: close conn: %v", err)
+		}
+	}()
+
+	// Reset idle timer on activity
+	t.mu.Lock()
+	t.resetTimerLocked()
+	t.mu.Unlock()
+
+	localAddr := &net.TCPAddr{
+		IP:   id.LocalAddress.AsSlice(),
+		Port: int(id.LocalPort),
+	}
+	remoteAddr := &net.TCPAddr{
+		IP:   id.RemoteAddress.AsSlice(),
+		Port: int(id.RemotePort),
+	}
+
+	for {
+		if err := conn.SetReadDeadline(time.Now().Add(dnsTCPReadTimeout)); err != nil {
+			log.Debugf("TCP DNS: set deadline for %s: %v", remoteAddr, err)
+			break
+		}
+
+		msg, err := readTCPDNSMessage(conn)
+		if err != nil {
+			if !errors.Is(err, io.EOF) && !errors.Is(err, io.ErrUnexpectedEOF) {
+				log.Debugf("TCP DNS: read from %s: %v", remoteAddr, err)
+			}
+			break
+		}
+
+		writer := &tcpResponseWriter{
+			conn:       conn,
+			localAddr:  localAddr,
+			remoteAddr: remoteAddr,
+		}
+		t.mux.ServeDNS(writer, msg)
+	}
+}
+
+// dnsEndpoint implements stack.LinkEndpoint for writing packets back via the tun device.
+type dnsEndpoint struct {
+	dispatcher stack.NetworkDispatcher
+	tunDev     tun.Device
+	mtu        atomic.Uint32
+}
+
+func (e *dnsEndpoint) Attach(dispatcher stack.NetworkDispatcher)    { e.dispatcher = dispatcher }
+func (e *dnsEndpoint) IsAttached() bool                             { return e.dispatcher != nil }
+func (e *dnsEndpoint) MTU() uint32                                  { return e.mtu.Load() }
+func (e *dnsEndpoint) Capabilities() stack.LinkEndpointCapabilities { return stack.CapabilityNone }
+func (e *dnsEndpoint) MaxHeaderLength() uint16                      { return 0 }
+func (e *dnsEndpoint) LinkAddress() tcpip.LinkAddress               { return "" }
+func (e *dnsEndpoint) Wait()                                        { /* no async work */ }
+func (e *dnsEndpoint) ARPHardwareType() header.ARPHardwareType      { return header.ARPHardwareNone }
+func (e *dnsEndpoint) AddHeader(*stack.PacketBuffer)                { /* IP-level endpoint, no link header */ }
+func (e *dnsEndpoint) ParseHeader(*stack.PacketBuffer) bool         { return true }
+func (e *dnsEndpoint) Close()                                       { /* lifecycle managed by tcpDNSServer */ }
+func (e *dnsEndpoint) SetLinkAddress(tcpip.LinkAddress)             { /* no link address for tun */ }
+func (e *dnsEndpoint) SetMTU(mtu uint32)                            { e.mtu.Store(mtu) }
+func (e *dnsEndpoint) SetOnCloseAction(func())                      { /* not needed */ }
+
+const tunPacketOffset = 40
+
+func (e *dnsEndpoint) WritePackets(pkts stack.PacketBufferList) (int, tcpip.Error) {
+	var written int
+	for _, pkt := range pkts.AsSlice() {
+		data := stack.PayloadSince(pkt.NetworkHeader())
+		if data == nil {
+			continue
+		}
+
+		raw := data.AsSlice()
+		buf := make([]byte, tunPacketOffset, tunPacketOffset+len(raw))
+		buf = append(buf, raw...)
+		data.Release()
+
+		if _, err := e.tunDev.Write([][]byte{buf}, tunPacketOffset); err != nil {
+			log.Tracef("TCP DNS endpoint: failed to write packet: %v", err)
+			continue
+		}
+		written++
+	}
+	return written, nil
+}
+
+// tcpResponseWriter implements dns.ResponseWriter for TCP DNS connections.
+type tcpResponseWriter struct {
+	conn       *gonet.TCPConn
+	localAddr  net.Addr
+	remoteAddr net.Addr
+}
+
+func (w *tcpResponseWriter) LocalAddr() net.Addr {
+	return w.localAddr
+}
+
+func (w *tcpResponseWriter) RemoteAddr() net.Addr {
+	return w.remoteAddr
+}
+
+func (w *tcpResponseWriter) WriteMsg(msg *dns.Msg) error {
+	data, err := msg.Pack()
+	if err != nil {
+		return fmt.Errorf("pack: %w", err)
+	}
+
+	// DNS TCP: 2-byte length prefix + message
+	buf := make([]byte, 2+len(data))
+	buf[0] = byte(len(data) >> 8)
+	buf[1] = byte(len(data))
+	copy(buf[2:], data)
+
+	if _, err = w.conn.Write(buf); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (w *tcpResponseWriter) Write(data []byte) (int, error) {
+	buf := make([]byte, 2+len(data))
+	buf[0] = byte(len(data) >> 8)
+	buf[1] = byte(len(data))
+	copy(buf[2:], data)
+	if _, err := w.conn.Write(buf); err != nil {
+		return 0, err
+	}
+	return len(data), nil
+}
+
+func (w *tcpResponseWriter) Close() error {
+	return w.conn.Close()
+}
+
+func (w *tcpResponseWriter) TsigStatus() error   { return nil }
+func (w *tcpResponseWriter) TsigTimersOnly(bool) { /* TSIG not supported */ }
+func (w *tcpResponseWriter) Hijack()             { /* not supported */ }
+
+// readTCPDNSMessage reads a single DNS message from a TCP connection (length-prefixed).
+func readTCPDNSMessage(conn *gonet.TCPConn) (*dns.Msg, error) {
+	// DNS over TCP uses a 2-byte length prefix
+	lenBuf := make([]byte, 2)
+	if _, err := io.ReadFull(conn, lenBuf); err != nil {
+		return nil, fmt.Errorf("read length: %w", err)
+	}
+
+	msgLen := int(lenBuf[0])<<8 | int(lenBuf[1])
+	if msgLen == 0 || msgLen > 65535 {
+		return nil, fmt.Errorf("invalid message length: %d", msgLen)
+	}
+
+	msgBuf := make([]byte, msgLen)
+	if _, err := io.ReadFull(conn, msgBuf); err != nil {
+		return nil, fmt.Errorf("read message: %w", err)
+	}
+
+	msg := new(dns.Msg)
+	if err := msg.Unpack(msgBuf); err != nil {
+		return nil, fmt.Errorf("unpack: %w", err)
+	}
+	return msg, nil
+}
+
+// srcAddrFromPacket extracts the source IP:port from a raw IP+TCP packet for logging.
+// Supports both IPv4 and IPv6.
+func srcAddrFromPacket(pkt []byte) netip.AddrPort {
+	if len(pkt) == 0 {
+		return netip.AddrPort{}
+	}
+
+	srcIP, transportOffset := srcIPFromPacket(pkt)
+	if !srcIP.IsValid() || len(pkt) < transportOffset+2 {
+		return netip.AddrPort{}
+	}
+
+	srcPort := uint16(pkt[transportOffset])<<8 | uint16(pkt[transportOffset+1])
+	return netip.AddrPortFrom(srcIP.Unmap(), srcPort)
+}
+
+func srcIPFromPacket(pkt []byte) (netip.Addr, int) {
+	switch header.IPVersion(pkt) {
+	case 4:
+		return srcIPv4(pkt)
+	case 6:
+		return srcIPv6(pkt)
+	default:
+		return netip.Addr{}, 0
+	}
+}
+
+func srcIPv4(pkt []byte) (netip.Addr, int) {
+	if len(pkt) < header.IPv4MinimumSize {
+		return netip.Addr{}, 0
+	}
+	hdr := header.IPv4(pkt)
+	src := hdr.SourceAddress()
+	ip, ok := netip.AddrFromSlice(src.AsSlice())
+	if !ok {
+		return netip.Addr{}, 0
+	}
+	return ip, int(hdr.HeaderLength())
+}
+
+func srcIPv6(pkt []byte) (netip.Addr, int) {
+	if len(pkt) < header.IPv6MinimumSize {
+		return netip.Addr{}, 0
+	}
+	hdr := header.IPv6(pkt)
+	src := hdr.SourceAddress()
+	ip, ok := netip.AddrFromSlice(src.AsSlice())
+	if !ok {
+		return netip.Addr{}, 0
+	}
+	return ip, header.IPv6MinimumSize
+}

client/internal/dns/upstream.go

@@ -29,6 +29,27 @@ import (
 
 var currentMTU uint16 = iface.DefaultMTU
 
+// nonRetryableEDECodes lists EDE info codes (RFC 8914) for which a SERVFAIL
+// from one upstream means another upstream would return the same answer:
+// DNSSEC validation outcomes and policy-based blocks. Transient errors
+// (network, cached, not ready) are not included.
+var nonRetryableEDECodes = map[uint16]struct{}{
+	dns.ExtendedErrorCodeUnsupportedDNSKEYAlgorithm: {},
+	dns.ExtendedErrorCodeUnsupportedDSDigestType:    {},
+	dns.ExtendedErrorCodeDNSSECIndeterminate:        {},
+	dns.ExtendedErrorCodeDNSBogus:                   {},
+	dns.ExtendedErrorCodeSignatureExpired:           {},
+	dns.ExtendedErrorCodeSignatureNotYetValid:       {},
+	dns.ExtendedErrorCodeDNSKEYMissing:              {},
+	dns.ExtendedErrorCodeRRSIGsMissing:              {},
+	dns.ExtendedErrorCodeNoZoneKeyBitSet:            {},
+	dns.ExtendedErrorCodeNSECMissing:                {},
+	dns.ExtendedErrorCodeBlocked:                    {},
+	dns.ExtendedErrorCodeCensored:                   {},
+	dns.ExtendedErrorCodeFiltered:                   {},
+	dns.ExtendedErrorCodeProhibited:                 {},
+}
+
 func SetCurrentMTU(mtu uint16) {
 	currentMTU = mtu
 }
@@ -41,10 +62,61 @@ const (
 
 	reactivatePeriod = 30 * time.Second
 	probeTimeout     = 2 * time.Second
+
+	// ipv6HeaderSize + udpHeaderSize, used to derive the maximum DNS UDP
+	// payload from the tunnel MTU.
+	ipUDPHeaderSize = 60 + 8
 )
 
 const testRecord = "com."
 
+const (
+	protoUDP = "udp"
+	protoTCP = "tcp"
+)
+
+type dnsProtocolKey struct{}
+
+// contextWithDNSProtocol stores the inbound DNS protocol ("udp" or "tcp") in context.
+func contextWithDNSProtocol(ctx context.Context, network string) context.Context {
+	return context.WithValue(ctx, dnsProtocolKey{}, network)
+}
+
+// dnsProtocolFromContext retrieves the inbound DNS protocol from context.
+func dnsProtocolFromContext(ctx context.Context) string {
+	if ctx == nil {
+		return ""
+	}
+	if v, ok := ctx.Value(dnsProtocolKey{}).(string); ok {
+		return v
+	}
+	return ""
+}
+
+type upstreamProtocolKey struct{}
+
+// upstreamProtocolResult holds the protocol used for the upstream exchange.
+// Stored as a pointer in context so the exchange function can set it.
+type upstreamProtocolResult struct {
+	protocol string
+}
+
+// contextWithupstreamProtocolResult stores a mutable result holder in the context.
+func contextWithupstreamProtocolResult(ctx context.Context) (context.Context, *upstreamProtocolResult) {
+	r := &upstreamProtocolResult{}
+	return context.WithValue(ctx, upstreamProtocolKey{}, r), r
+}
+
+// setUpstreamProtocol sets the upstream protocol on the result holder in context, if present.
+func setUpstreamProtocol(ctx context.Context, protocol string) {
+	if ctx == nil {
+		return
+	}
+	if r, ok := ctx.Value(upstreamProtocolKey{}).(*upstreamProtocolResult); ok && r != nil {
+		r.protocol = protocol
+	}
+}
+
 type upstreamClient interface {
 	exchange(ctx context.Context, upstream string, r *dns.Msg) (*dns.Msg, time.Duration, error)
 }
@@ -138,7 +210,16 @@ func (u *upstreamResolverBase) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 		return
 	}
 
-	ok, failures := u.tryUpstreamServers(w, r, logger)
+	// Propagate inbound protocol so upstream exchange can use TCP directly
+	// when the request came in over TCP.
+	ctx := u.ctx
+	if addr := w.RemoteAddr(); addr != nil {
+		network := addr.Network()
+		ctx = contextWithDNSProtocol(ctx, network)
+		resutil.SetMeta(w, "protocol", network)
+	}
+
+	ok, failures := u.tryUpstreamServers(ctx, w, r, logger)
 	if len(failures) > 0 {
 		u.logUpstreamFailures(r.Question[0].Name, failures, ok, logger)
 	}
@@ -153,7 +234,7 @@ func (u *upstreamResolverBase) prepareRequest(r *dns.Msg) {
 	}
 }
 
-func (u *upstreamResolverBase) tryUpstreamServers(w dns.ResponseWriter, r *dns.Msg, logger *log.Entry) (bool, []upstreamFailure) {
+func (u *upstreamResolverBase) tryUpstreamServers(ctx context.Context, w dns.ResponseWriter, r *dns.Msg, logger *log.Entry) (bool, []upstreamFailure) {
 	timeout := u.upstreamTimeout
 	if len(u.upstreamServers) > 1 {
 		maxTotal := 5 * time.Second
@@ -168,7 +249,7 @@ func (u *upstreamResolverBase) tryUpstreamServers(w dns.ResponseWriter, r *dns.M
 
 	var failures []upstreamFailure
 	for _, upstream := range u.upstreamServers {
-		if failure := u.queryUpstream(w, r, upstream, timeout, logger); failure != nil {
+		if failure := u.queryUpstream(ctx, w, r, upstream, timeout, logger); failure != nil {
 			failures = append(failures, *failure)
 		} else {
 			return true, failures
@@ -178,17 +259,31 @@ func (u *upstreamResolverBase) tryUpstreamServers(w dns.ResponseWriter, r *dns.M
 }
 
 // queryUpstream queries a single upstream server. Returns nil on success, or failure info to try next upstream.
-func (u *upstreamResolverBase) queryUpstream(w dns.ResponseWriter, r *dns.Msg, upstream netip.AddrPort, timeout time.Duration, logger *log.Entry) *upstreamFailure {
+func (u *upstreamResolverBase) queryUpstream(parentCtx context.Context, w dns.ResponseWriter, r *dns.Msg, upstream netip.AddrPort, timeout time.Duration, logger *log.Entry) *upstreamFailure {
 	var rm *dns.Msg
 	var t time.Duration
 	var err error
 
+	// Advertise EDNS0 so the upstream may include Extended DNS Errors
+	// (RFC 8914) in failure responses; we use those to short-circuit
+	// failover for definitive answers like DNSSEC validation failures.
+	// Operate on a copy so the inbound request is unchanged: a client that
+	// did not advertise EDNS0 must not see an OPT in the response.
+	hadEdns := r.IsEdns0() != nil
+	reqUp := r
+	if !hadEdns {
+		reqUp = r.Copy()
+		reqUp.SetEdns0(upstreamUDPSize(), false)
+	}
+
 	var startTime time.Time
+	var upstreamProto *upstreamProtocolResult
 	func() {
-		ctx, cancel := context.WithTimeout(u.ctx, timeout)
+		ctx, cancel := context.WithTimeout(parentCtx, timeout)
 		defer cancel()
+		ctx, upstreamProto = contextWithupstreamProtocolResult(ctx)
 		startTime = time.Now()
-		rm, t, err = u.upstreamClient.exchange(ctx, upstream.String(), r)
+		rm, t, err = u.upstreamClient.exchange(ctx, upstream.String(), reqUp)
 	}()
 
 	if err != nil {
@@ -200,13 +295,49 @@ func (u *upstreamResolverBase) queryUpstream(w dns.ResponseWriter, r *dns.Msg, u
 	}
 
 	if rm.Rcode == dns.RcodeServerFailure || rm.Rcode == dns.RcodeRefused {
+		if code, ok := nonRetryableEDE(rm); ok {
+			resutil.SetMeta(w, "ede", edeName(code))
+			if !hadEdns {
+				stripOPT(rm)
+			}
+			u.writeSuccessResponse(w, rm, upstream, r.Question[0].Name, t, upstreamProto, logger)
+			return nil
+		}
 		return &upstreamFailure{upstream: upstream, reason: dns.RcodeToString[rm.Rcode]}
 	}
 
-	u.writeSuccessResponse(w, rm, upstream, r.Question[0].Name, t, logger)
+	if !hadEdns {
+		stripOPT(rm)
+	}
+	u.writeSuccessResponse(w, rm, upstream, r.Question[0].Name, t, upstreamProto, logger)
 	return nil
 }
 
+// upstreamUDPSize returns the EDNS0 UDP buffer size we advertise to upstreams,
+// derived from the tunnel MTU and bounded against underflow.
+func upstreamUDPSize() uint16 {
+	if currentMTU > ipUDPHeaderSize {
+		return currentMTU - ipUDPHeaderSize
+	}
+	return dns.MinMsgSize
+}
+
+// stripOPT removes any OPT pseudo-RRs from the response's Extra section so
+// the response complies with RFC 6891 when the client did not advertise EDNS0.
+func stripOPT(rm *dns.Msg) {
+	if len(rm.Extra) == 0 {
+		return
+	}
+	out := rm.Extra[:0]
+	for _, rr := range rm.Extra {
+		if _, ok := rr.(*dns.OPT); ok {
+			continue
+		}
+		out = append(out, rr)
+	}
+	rm.Extra = out
+}
+
 func (u *upstreamResolverBase) handleUpstreamError(err error, upstream netip.AddrPort, startTime time.Time) *upstreamFailure {
 	if !errors.Is(err, context.DeadlineExceeded) && !isTimeout(err) {
 		return &upstreamFailure{upstream: upstream, reason: err.Error()}
@@ -220,10 +351,13 @@ func (u *upstreamResolverBase) handleUpstreamError(err error, upstream netip.Add
 	return &upstreamFailure{upstream: upstream, reason: reason}
 }
 
-func (u *upstreamResolverBase) writeSuccessResponse(w dns.ResponseWriter, rm *dns.Msg, upstream netip.AddrPort, domain string, t time.Duration, logger *log.Entry) bool {
+func (u *upstreamResolverBase) writeSuccessResponse(w dns.ResponseWriter, rm *dns.Msg, upstream netip.AddrPort, domain string, t time.Duration, upstreamProto *upstreamProtocolResult, logger *log.Entry) bool {
 	u.successCount.Add(1)
 
 	resutil.SetMeta(w, "upstream", upstream.String())
+	if upstreamProto != nil && upstreamProto.protocol != "" {
+		resutil.SetMeta(w, "upstream_protocol", upstreamProto.protocol)
+	}
 
 	// Clear Zero bit from external responses to prevent upstream servers from
 	// manipulating our internal fallthrough signaling mechanism
@@ -265,6 +399,34 @@ func formatFailures(failures []upstreamFailure) string {
 	return strings.Join(parts, ", ")
 }
 
+// nonRetryableEDE returns the first non-retryable EDE code carried in the
+// response, if any.
+func nonRetryableEDE(rm *dns.Msg) (uint16, bool) {
+	opt := rm.IsEdns0()
+	if opt == nil {
+		return 0, false
+	}
+	for _, o := range opt.Option {
+		ede, ok := o.(*dns.EDNS0_EDE)
+		if !ok {
+			continue
+		}
+		if _, ok := nonRetryableEDECodes[ede.InfoCode]; ok {
+			return ede.InfoCode, true
+		}
+	}
+	return 0, false
+}
+
+// edeName returns a human-readable name for an EDE code, falling back to
+// the numeric code when unknown.
+func edeName(code uint16) string {
+	if name, ok := dns.ExtendedErrorCodeToString[code]; ok {
+		return name
+	}
+	return fmt.Sprintf("EDE %d", code)
+}
+
 // ProbeAvailability tests all upstream servers simultaneously and
 // disables the resolver if none work
 func (u *upstreamResolverBase) ProbeAvailability(ctx context.Context) {
@@ -428,13 +590,42 @@ func (u *upstreamResolverBase) testNameserver(baseCtx context.Context, externalC
 	return err
 }
 
+// clientUDPMaxSize returns the maximum UDP response size the client accepts.
+func clientUDPMaxSize(r *dns.Msg) int {
+	if opt := r.IsEdns0(); opt != nil {
+		return int(opt.UDPSize())
+	}
+	return dns.MinMsgSize
+}
+
 // ExchangeWithFallback exchanges a DNS message with the upstream server.
 // It first tries to use UDP, and if it is truncated, it falls back to TCP.
+// If the inbound request came over TCP (via context), it skips the UDP attempt.
 // If the passed context is nil, this will use Exchange instead of ExchangeContext.
 func ExchangeWithFallback(ctx context.Context, client *dns.Client, r *dns.Msg, upstream string) (*dns.Msg, time.Duration, error) {
-	// MTU - ip + udp headers
-	// Note: this could be sent out on an interface that is not ours, but higher MTU settings could break truncation handling.
-	client.UDPSize = uint16(currentMTU - (60 + 8))
+	// If the request came in over TCP, go straight to TCP upstream.
+	if dnsProtocolFromContext(ctx) == protoTCP {
+		tcpClient := *client
+		tcpClient.Net = protoTCP
+		rm, t, err := tcpClient.ExchangeContext(ctx, r, upstream)
+		if err != nil {
+			return nil, t, fmt.Errorf("with tcp: %w", err)
+		}
+		setUpstreamProtocol(ctx, protoTCP)
+		return rm, t, nil
+	}
+
+	clientMaxSize := clientUDPMaxSize(r)
+
+	// Cap EDNS0 to our tunnel MTU so the upstream doesn't send a
+	// response larger than our read buffer.
+	// Note: the query could be sent out on an interface that is not ours,
+	// but higher MTU settings could break truncation handling.
+	maxUDPPayload := uint16(currentMTU - ipUDPHeaderSize)
+	client.UDPSize = maxUDPPayload
+	if opt := r.IsEdns0(); opt != nil && opt.UDPSize() > maxUDPPayload {
+		opt.SetUDPSize(maxUDPPayload)
+	}
 
 	var (
 		rm  *dns.Msg
@@ -453,25 +644,32 @@ func ExchangeWithFallback(ctx context.Context, client *dns.Client, r *dns.Msg, u
 	}
 
 	if rm == nil || !rm.MsgHdr.Truncated {
+		setUpstreamProtocol(ctx, protoUDP)
 		return rm, t, nil
 	}
 
-	log.Tracef("udp response for domain=%s type=%v class=%v is truncated, trying TCP.",
-		r.Question[0].Name, r.Question[0].Qtype, r.Question[0].Qclass)
+	// TODO: if the upstream's truncated UDP response already contains more
+	// data than the client's buffer, we could truncate locally and skip
+	// the TCP retry.
 
-	client.Net = "tcp"
+	tcpClient := *client
+	tcpClient.Net = protoTCP
 
 	if ctx == nil {
-		rm, t, err = client.Exchange(r, upstream)
+		rm, t, err = tcpClient.Exchange(r, upstream)
 	} else {
-		rm, t, err = client.ExchangeContext(ctx, r, upstream)
+		rm, t, err = tcpClient.ExchangeContext(ctx, r, upstream)
 	}
 
 	if err != nil {
 		return nil, t, fmt.Errorf("with tcp: %w", err)
 	}
 
-	// TODO: once TCP is implemented, rm.Truncate() if the request came in over UDP
+	setUpstreamProtocol(ctx, protoTCP)
+
+	if rm.Len() > clientMaxSize {
+		rm.Truncate(clientMaxSize)
+	}
 
 	return rm, t, nil
 }
@@ -479,18 +677,46 @@ func ExchangeWithFallback(ctx context.Context, client *dns.Client, r *dns.Msg, u
 // ExchangeWithNetstack performs a DNS exchange using netstack for dialing.
 // This is needed when netstack is enabled to reach peer IPs through the tunnel.
 func ExchangeWithNetstack(ctx context.Context, nsNet *netstack.Net, r *dns.Msg, upstream string) (*dns.Msg, error) {
-	reply, err := netstackExchange(ctx, nsNet, r, upstream, "udp")
+	// If request came in over TCP, go straight to TCP upstream
+	if dnsProtocolFromContext(ctx) == protoTCP {
+		rm, err := netstackExchange(ctx, nsNet, r, upstream, protoTCP)
+		if err != nil {
+			return nil, err
+		}
+		setUpstreamProtocol(ctx, protoTCP)
+		return rm, nil
+	}
+
+	clientMaxSize := clientUDPMaxSize(r)
+
+	// Cap EDNS0 to our tunnel MTU so the upstream doesn't send a
+	// response larger than what we can read over UDP.
+	maxUDPPayload := uint16(currentMTU - ipUDPHeaderSize)
+	if opt := r.IsEdns0(); opt != nil && opt.UDPSize() > maxUDPPayload {
+		opt.SetUDPSize(maxUDPPayload)
+	}
+
+	reply, err := netstackExchange(ctx, nsNet, r, upstream, protoUDP)
 	if err != nil {
 		return nil, err
 	}
 
-	// If response is truncated, retry with TCP
 	if reply != nil && reply.MsgHdr.Truncated {
-		log.Tracef("udp response for domain=%s type=%v class=%v is truncated, trying TCP",
-			r.Question[0].Name, r.Question[0].Qtype, r.Question[0].Qclass)
-		return netstackExchange(ctx, nsNet, r, upstream, "tcp")
+		rm, err := netstackExchange(ctx, nsNet, r, upstream, protoTCP)
+		if err != nil {
+			return nil, err
+		}
+
+		setUpstreamProtocol(ctx, protoTCP)
+		if rm.Len() > clientMaxSize {
+			rm.Truncate(clientMaxSize)
+		}
+
+		return rm, nil
 	}
 
+	setUpstreamProtocol(ctx, protoUDP)
+
 	return reply, nil
 }
 
@@ -511,7 +737,7 @@ func netstackExchange(ctx context.Context, nsNet *netstack.Net, r *dns.Msg, upst
 		}
 	}
 
-	dnsConn := &dns.Conn{Conn: conn}
+	dnsConn := &dns.Conn{Conn: conn, UDPSize: uint16(currentMTU - ipUDPHeaderSize)}
 
 	if err := dnsConn.WriteMsg(r); err != nil {
 		return nil, fmt.Errorf("write %s message: %w", network, err)

client/internal/dns/upstream_android.go

@@ -51,7 +51,7 @@ func (u *upstreamResolver) exchangeWithinVPN(ctx context.Context, upstream strin
 	upstreamExchangeClient := &dns.Client{
 		Timeout: ClientTimeout,
 	}
-	return upstreamExchangeClient.ExchangeContext(ctx, r, upstream)
+	return ExchangeWithFallback(ctx, upstreamExchangeClient, r, upstream)
 }
 
 // exchangeWithoutVPN protect the UDP socket by Android SDK to avoid to goes through the VPN
@@ -76,7 +76,7 @@ func (u *upstreamResolver) exchangeWithoutVPN(ctx context.Context, upstream stri
 		Timeout: timeout,
 	}
 
-	return upstreamExchangeClient.ExchangeContext(ctx, r, upstream)
+	return ExchangeWithFallback(ctx, upstreamExchangeClient, r, upstream)
 }
 
 func (u *upstreamResolver) isLocalResolver(upstream string) bool {