Default local listeners to 127.0.0.1

Client TCP/UDP and the built-in DNS server bind loopback unless bind_address or a per-rule host (tcp://22:0.0.0.0:2222) is set. README and generated server examples no longer document :9000/:8080 as if they were localhost-only.

Closes #3

internal/client/client.go

@@ -93,9 +93,11 @@ func (tc *TeleportClient) startPortForwarding(rule config.PortRule) {
 
 // startTCPForwarding starts TCP port forwarding
 func (tc *TeleportClient) startTCPForwarding(rule config.PortRule) {
-	listener, err := net.Listen("tcp", fmt.Sprintf(":%d", rule.LocalPort))
+	listenAddr := tc.config.ClientListenAddr(rule)
+	listener, err := net.Listen("tcp", listenAddr)
 	if err != nil {
 		logger.WithFields(map[string]interface{}{
+			"addr":  listenAddr,
 			"port":  rule.LocalPort,
 			"error": err,
 		}).Error("Failed to start TCP listener")
@@ -104,6 +106,7 @@ func (tc *TeleportClient) startTCPForwarding(rule config.PortRule) {
 	defer listener.Close()
 
 	logger.WithFields(map[string]interface{}{
+		"listen_addr": listenAddr,
 		"local_port":  rule.LocalPort,
 		"remote_addr": tc.config.RemoteAddress,
 		"remote_port": rule.RemotePort,
@@ -254,9 +257,11 @@ func (tc *TeleportClient) returnConnection(conn net.Conn) {
 
 // startUDPForwarding starts UDP port forwarding
 func (tc *TeleportClient) startUDPForwarding(rule config.PortRule) {
-	addr, err := net.ResolveUDPAddr("udp", fmt.Sprintf(":%d", rule.LocalPort))
+	listenAddr := tc.config.ClientListenAddr(rule)
+	addr, err := net.ResolveUDPAddr("udp", listenAddr)
 	if err != nil {
 		logger.WithFields(map[string]interface{}{
+			"addr":  listenAddr,
 			"port":  rule.LocalPort,
 			"error": err,
 		}).Error("Failed to resolve UDP address")
@@ -266,6 +271,7 @@ func (tc *TeleportClient) startUDPForwarding(rule config.PortRule) {
 	conn, err := net.ListenUDP("udp", addr)
 	if err != nil {
 		logger.WithFields(map[string]interface{}{
+			"addr":  listenAddr,
 			"port":  rule.LocalPort,
 			"error": err,
 		}).Error("Failed to start UDP listener")
@@ -277,6 +283,7 @@ func (tc *TeleportClient) startUDPForwarding(rule config.PortRule) {
 	tc.udpMutex.Unlock()
 
 	logger.WithFields(map[string]interface{}{
+		"listen_addr": listenAddr,
 		"local_port":  rule.LocalPort,
 		"remote_addr": tc.config.RemoteAddress,
 		"remote_port": rule.RemotePort,
@@ -641,7 +648,12 @@ func (tc *TeleportClient) handleTCPConnection(clientConn net.Conn, rule config.P
 	defer tc.returnConnection(serverConn)
 
 	// Send port forward request to server
-	request := types.PortForwardRequest(rule)
+	request := types.PortForwardRequest{
+		LocalPort:  rule.LocalPort,
+		RemotePort: rule.RemotePort,
+		Protocol:   rule.Protocol,
+		TargetHost: rule.TargetHost,
+	}
 
 	if err := tc.sendRequestToConnection(serverConn, request); err != nil {
 		logger.WithField("error", err).Error("Failed to send port forward request")