Config > DisableNAT (#9)

Author: freemans13

client.go

@@ -186,9 +186,19 @@ func createHost(_ context.Context, hostOpts []libp2p.Option, config Config, rela
 			fmt.Sprintf("/ip4/0.0.0.0/tcp/%d", config.Port),
 			fmt.Sprintf("/ip6/::/tcp/%d", config.Port),
 		),
-		libp2p.NATPortMap(),
-		libp2p.EnableNATService(),
-		libp2p.EnableHolePunching(),
+	)
+
+	// Only enable NAT traversal features if not disabled
+	// NAT features can cause data races in tests due to libp2p's NAT manager using non-thread-safe global state
+	if !config.DisableNAT {
+		hostOpts = append(hostOpts,
+			libp2p.NATPortMap(),
+			libp2p.EnableNATService(),
+			libp2p.EnableHolePunching(),
+		)
+	}
+
+	hostOpts = append(hostOpts,
 		libp2p.EnableRelay(),
 		libp2p.EnableAutoRelayWithStaticRelays(relayPeers),
 	)

config.go

@@ -97,4 +97,10 @@ type Config struct {
 	// Recommended: 6-24 hours for production to reduce CPU overhead.
 	// The cleanup frequency trades off between memory usage (stale records) and CPU usage.
 	DHTCleanupInterval time.Duration
+
+	// DisableNAT disables NAT traversal features (UPnP/NAT-PMP port mapping, NAT service, hole punching).
+	// Set to true in test environments where NAT traversal is not needed and can cause data races
+	// due to libp2p's NAT manager using non-thread-safe global state.
+	// Default: false (NAT features enabled)
+	DisableNAT bool
 }