2d8b0310a4
Two related fixes for the embedded netbird client and the per-account
inbound listeners that ride on its gVisor netstack.
client/internal/engine.go — replace hasIPv6Changed with reconcileIPv6:
- First v6 assignment (current had no v6, conf carries one) is applied
in place via WGIface.UpdateAddr instead of returning ErrResetConnection.
Pre-fix, every embedded client whose account had IPv6 enabled would
reset on its first NetworkMap sync — boot config has no v6, the sync
introduces one, the engine tore itself down to "apply" it. That
teardown destroys the gVisor netstack and orphans every listener
bound on it, which is what made the proxy's per-account :80/:443
silently stop accepting traffic.
- v6 removed clears in place.
- v6 swapped to a different non-empty value still resets (gVisor
netstack can't safely swap its address at runtime).
- Mutates e.config.WgAddr to match the applied state so subsequent
PeerConfig comparisons are stable.
proxy/internal/tcp/accept.go (new) + proxy/inbound.go +
proxy/internal/tcp/router.go — harden the two Accept() loops on
netstack-backed listeners:
- IsClosedListenerErr recognises net.ErrClosed AND gVisor's
"endpoint is in invalid state" — the latter survives gonet's
*net.OpError wrapping in a way errors.Is(.., net.ErrClosed) does
not. Without this the loop spins CPU-hot after the underlying
netstack is destroyed (peer rekey, embedded-client reset, account
churn), emitting one log line per iteration.
- AcceptBackoff implements the exponential backoff that
net/http.Server.Serve uses on transient Accept errors: 5ms doubling
up to 1s. Defence-in-depth so an unknown sticky error cannot burn
a CPU core even if IsClosedListenerErr misses its signature.
proxy/internal/roundtrip/netbird.go — emit a single structured INFO
line summarising every embed.Options flag (account_id, service_id,
public_key, management_url, wg_port, block_inbound, block_lan_access,
disable_ipv6, no_userspace, presence of credentials) when each
per-account embedded client is created. Secrets reduced to a "present"
boolean — never logged verbatim. Diagnostic-only; no behavior change,
but it makes the "why is this embedded peer misbehaving" loop a single
log read instead of a code dive.
Tests (real listeners, scripted errors, no mocks of production code):
- engine_reconcileipv6_test.go: 8 cases for every transition (first
assignment, no change, removed, prefix-length changed, value
changed, invalid bytes, UpdateAddr error) plus a updateConfig
integration check that the fix actually fires on a v6-added
PeerConfig.
- accept_test.go: IsClosedListenerErr matrix + AcceptBackoff
progression / cap / reset / cancel-during-wait / cancel-before-call.
- router_test.go, inbound_test.go: scriptedAcceptListener +
TestRouter_Serve_ExitsOnGVisorInvalidEndpoint and
TestFeedRouterFromListener_ExitsOnGVisorInvalidEndpoint —
regression guards that fail in 2 s if the loop ever spins.
Netbird Reverse Proxy
The NetBird Reverse Proxy is a separate service that can act as a public entrypoint to certain resources within a NetBird network. At a high level, the way that it operates is:
- Configured routes are communicated from the Management server to the proxy.
- For each route the proxy creates a NetBird connection to the NetBird Peer that hosts the resource.
- When traffic hits the proxy at the address and path configured for the proxied resource, the NetBird Proxy brings up a relevant authentication method for that resource.
- On successful authentication the proxy will forward traffic onwards to the NetBird Peer.
Proxy Authentication methods supported are:
- No authentication
- Oauth2/OIDC
- Emailed Magic Link
- Simple PIN
- HTTP Basic Auth Username and Password
Management Connection and Authentication
The Proxy communicates with the Management server over a gRPC connection. Proxies act as clients to the Management server, the following RPCs are used:
- Server-side streaming for proxied service updates.
- Client-side streaming for proxy logs.
To authenticate with the Management server, the proxy server uses Machine-to-Machine OAuth2. If you are using the embedded IdP //TODO: explain how to get credentials. Otherwise, create a new machine-to-machine profile in your IdP for proxy servers and set the relevant settings in the proxy's environment or flags (see below).
User Authentication
When a request hits the Proxy, it looks up the permitted authentication methods for the Host domain. If no authentication methods are registered for the Host domain, then no authentication will be applied (for fully public resources). If any authentication methods are registered for the Host domain, then the Proxy will first serve an authentication page allowing the user to select an authentication method (from the permitted methods) and enter the required information for that authentication method. If the user is successfully authenticated, their request will be forwarded through to the Proxy to be proxied to the relevant Peer. Successful authentication does not guarantee a successful forwarding of the request as there may be failures behind the Proxy, such as with Peer connectivity or the underlying resource.
TLS
Due to the authentication provided, the Proxy uses HTTPS for its endpoint, even if the underlying service is HTTP.
Certificate generation can either be via ACME (by default, using Let's Encrypt, but alternative ACME providers can be used) or through certificate files.
When not using ACME, the proxy server attempts to load a certificate and key from the files tls.crt and tls.key in a specified certificate directory.
When using ACME, the proxy server will store generated certificates in the specified certificate directory.
Auth UI
The authentication UI is a Vite + React application located in the web/ directory. It is embedded into the Go binary at build time.
To build the UI:
cd web
npm install
npm run build
For UI development with hot reload (served at http://localhost:3031):
npm run dev
The built assets in web/dist/ are embedded via //go:embed and served by the web.ServeHTTP handler.
Configuration
NetBird Proxy deployment configuration is via flags or environment variables, with flags taking precedence over the environment. The following deployment configuration is available:
| Flag | Env | Purpose | Default |
|---|---|---|---|
-debug |
NB_PROXY_DEBUG_LOGS |
Enable debug logging | false |
-mgmt |
NB_PROXY_MANAGEMENT_ADDRESS |
The address of the management server for the proxy to get configuration from. | "https://api.netbird.io:443" |
-addr |
NB_PROXY_ADDRESS |
The address that the reverse proxy will listen on. | ":443 |
-url |
NB_PROXY_URL |
The URL that the proxy will be reached at (where endpoints will be CNAMEd to). If unset, this will fall back to the proxy address. | "proxy.netbird.io" |
-cert-dir |
NB_PROXY_CERTIFICATE_DIRECTORY |
The location that certificates are stored in. | "./certs" |
-acme-certs |
NB_PROXY_ACME_CERTIFICATES |
Whether to use ACME to generate certificates. | false |
-acme-addr |
NB_PROXY_ACME_ADDRESS |
The HTTP address the proxy will listen on to respond to HTTP-01 ACME challenges | ":80" |
-acme-dir |
NB_PROXY_ACME_DIRECTORY |
The directory URL of the ACME server to be used | "https://acme-v02.api.letsencrypt.org/directory" |
-oidc-id |
NB_PROXY_OIDC_CLIENT_ID |
The OAuth2 Client ID for OIDC User Authentication | "netbird-proxy" |
-oidc-secret |
NB_PROXY_OIDC_CLIENT_SECRET |
The OAuth2 Client Secret for OIDC User Authentication | "" |
-oidc-endpoint |
NB_PROXY_OIDC_ENDPOINT |
The OAuth2 provider endpoint for OIDC User Authentication | "https://api.netbird.io/oauth2" |
-oidc-scopes |
NB_PROXY_OIDC_SCOPES |
The OAuth2 scopes for OIDC User Authentication, comma separated | "openid,profile,email" |