Use Go's resolver for darwin for control plane and ICE traffic

client/net/dialer.go

@@ -13,7 +13,9 @@ type Dialer struct {
 // NewDialer returns a customized net.Dialer with overridden Control method
 func NewDialer() *Dialer {
 	dialer := &Dialer{
-		Dialer: &net.Dialer{},
+		Dialer: &net.Dialer{
+			Resolver: NewResolver(),
+		},
 	}
 	dialer.init()
 	return dialer

client/net/resolver.go

@@ -0,0 +1,43 @@
+package net
+
+import (
+	"net"
+	"os"
+	"runtime"
+	"strings"
+)
+
+const (
+	// EnvResolver is the environment variable to control DNS resolver behavior
+	// Values: "system" (use system resolver), "go" (use pure Go resolver), empty (auto-detect)
+	EnvResolver = "NB_DNS_RESOLVER"
+)
+
+// NewResolver creates a DNS resolver with appropriate settings based on platform and configuration.
+// On Darwin (macOS), it defaults to the pure Go resolver to avoid getaddrinfo hangs after sleep/wake.
+// This is particularly important for connections using this package's Dialer, which bypasses the NetBird
+// overlay network for control plane traffic. Since these connections target external infrastructure
+// (management, signal, relay servers), it is safe to ignore split DNS configurations that would
+// normally be provided by the system resolver.
+// On other platforms, it uses the system resolver (cgo).
+// This behavior can be overridden using the NB_DNS_RESOLVER environment variable or GODEBUG.
+func NewResolver() *net.Resolver {
+	if resolver := os.Getenv(EnvResolver); resolver != "" {
+		switch strings.ToLower(resolver) {
+		case "system":
+			return net.DefaultResolver
+		case "go":
+			return &net.Resolver{
+				PreferGo: true,
+			}
+		}
+	}
+
+	if runtime.GOOS == "darwin" {
+		return &net.Resolver{
+			PreferGo: true,
+		}
+	}
+
+	return net.DefaultResolver
+}