feat: Change default listen address to 0.0.0.0

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -11,6 +11,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 ### Added
 
 ### Changed
+- The default listen address of `UnityTransport` is now 0.0.0.0. (#2307)
 
 ### Fixed
 

com.unity.netcode.gameobjects/Runtime/Transports/UTP/UnityTransport.cs

@@ -303,9 +303,9 @@ public struct ConnectionAddressData
             public ushort Port;
 
             /// <summary>
-            /// IP address the server will listen on. If not provided, will use 'Address'.
+            /// IP address the server will listen on. If not provided, will use 0.0.0.0.
             /// </summary>
-            [Tooltip("IP address the server will listen on. If not provided, will use 'Address'.")]
+            [Tooltip("IP address the server will listen on. If not provided, will use 0.0.0.0.")]
             [SerializeField]
             public string ServerListenAddress;
 
@@ -330,7 +330,29 @@ private static NetworkEndpoint ParseNetworkEndpoint(string ip, ushort port)
             /// <summary>
             /// Endpoint (IP address and port) server will listen/bind on.
             /// </summary>
-            public NetworkEndpoint ListenEndPoint => ParseNetworkEndpoint((ServerListenAddress?.Length == 0) ? Address : ServerListenAddress, Port);
+            public NetworkEndpoint ListenEndPoint
+            {
+                get
+                {
+                    if (string.IsNullOrEmpty(ServerListenAddress))
+                    {
+                        var ep = NetworkEndpoint.AnyIpv4;
+
+                        // If an address was entered and it's IPv6, switch to using :: as the
+                        // default listen address. (Otherwise we always assume IPv4.)
+                        if (!string.IsNullOrEmpty(Address) && ServerEndPoint.Family == NetworkFamily.Ipv6)
+                        {
+                            ep = NetworkEndpoint.AnyIpv6;
+                        }
+
+                        return ep.WithPort(Port);
+                    }
+                    else
+                    {
+                        return ParseNetworkEndpoint(ServerListenAddress, Port);
+                    }
+                }
+            }
         }
 
         /// <summary>
@@ -529,14 +551,14 @@ private bool ServerBindAndListen(NetworkEndpoint endPoint)
             int result = m_Driver.Bind(endPoint);
             if (result != 0)
             {
-                Debug.LogError("Server failed to bind");
+                Debug.LogError("Server failed to bind. This is usually caused by another process being bound to the same port.");
                 return false;
             }
 
             result = m_Driver.Listen();
             if (result != 0)
             {
-                Debug.LogError("Server failed to listen");
+                Debug.LogError("Server failed to listen.");
                 return false;
             }
 
@@ -1473,7 +1495,7 @@ public void CreateDriver(UnityTransport transport, out NetworkDriver driver,
                 {
                     if (NetworkManager.IsServer)
                     {
-                        if (String.IsNullOrEmpty(m_ServerCertificate) || String.IsNullOrEmpty(m_ServerPrivateKey))
+                        if (string.IsNullOrEmpty(m_ServerCertificate) || string.IsNullOrEmpty(m_ServerPrivateKey))
                         {
                             throw new Exception("In order to use encrypted communications, when hosting, you must set the server certificate and key.");
                         }
@@ -1482,11 +1504,11 @@ public void CreateDriver(UnityTransport transport, out NetworkDriver driver,
                     }
                     else
                     {
-                        if (String.IsNullOrEmpty(m_ServerCommonName))
+                        if (string.IsNullOrEmpty(m_ServerCommonName))
                         {
                             throw new Exception("In order to use encrypted communications, clients must set the server common name.");
                         }
-                        else if (String.IsNullOrEmpty(m_ClientCaCertificate))
+                        else if (string.IsNullOrEmpty(m_ClientCaCertificate))
                         {
                             m_NetworkSettings.WithSecureClientParameters(m_ServerCommonName);
                         }

com.unity.netcode.gameobjects/Tests/Editor/Transports/UnityTransportTests.cs

@@ -115,13 +115,26 @@ public void UnityTransport_RestartSucceedsAfterFailure()
             UnityTransport transport = new GameObject().AddComponent<UnityTransport>();
             transport.Initialize();
 
-            transport.SetConnectionData("127.0.0.", 4242);
+            transport.SetConnectionData("127.0.0.", 4242, "127.0.0.");
             Assert.False(transport.StartServer());
 
             LogAssert.Expect(LogType.Error, "Invalid network endpoint: 127.0.0.:4242.");
-            LogAssert.Expect(LogType.Error, "Server failed to bind");
+            LogAssert.Expect(LogType.Error, "Server failed to bind. This is usually caused by another process being bound to the same port.");
 
-            transport.SetConnectionData("127.0.0.1", 4242);
+            transport.SetConnectionData("127.0.0.1", 4242, "127.0.0.1");
+            Assert.True(transport.StartServer());
+
+            transport.Shutdown();
+        }
+
+        // Check that leaving all addresses empty is valid.
+        [Test]
+        public void UnityTransport_StartServerWithoutAddresses()
+        {
+            UnityTransport transport = new GameObject().AddComponent<UnityTransport>();
+            transport.Initialize();
+
+            transport.SetConnectionData(string.Empty, 4242);
             Assert.True(transport.StartServer());
 
             transport.Shutdown();