Index: source/lobby/IXmppClient.h
===================================================================
--- source/lobby/IXmppClient.h
+++ source/lobby/IXmppClient.h
@@ -39,7 +39,7 @@
 	virtual void SendIqGetProfile(const std::string& player) = 0;
 	virtual void SendIqGameReport(const ScriptInterface& scriptInterface, JS::HandleValue data) = 0;
 	virtual void SendIqRegisterGame(const ScriptInterface& scriptInterface, JS::HandleValue data) = 0;
-	virtual void SendIqGetConnectionData(const std::string& jid, const std::string& password) = 0;
+	virtual void SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP) = 0;
 	virtual void SendIqUnregisterGame() = 0;
 	virtual void SendIqChangeStateGame(const std::string& nbp, const std::string& players) = 0;
 	virtual void SendIqLobbyAuth(const std::string& to, const std::string& token) = 0;
Index: source/lobby/XmppClient.h
===================================================================
--- source/lobby/XmppClient.h
+++ source/lobby/XmppClient.h
@@ -86,7 +86,7 @@
 	void SendIqGetProfile(const std::string& player);
 	void SendIqGameReport(const ScriptInterface& scriptInterface, JS::HandleValue data);
 	void SendIqRegisterGame(const ScriptInterface& scriptInterface, JS::HandleValue data);
-	void SendIqGetConnectionData(const std::string& jid, const std::string& password);
+	void SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP);
 	void SendIqUnregisterGame();
 	void SendIqChangeStateGame(const std::string& nbp, const std::string& players);
 	void SendIqLobbyAuth(const std::string& to, const std::string& token);
Index: source/lobby/XmppClient.cpp
===================================================================
--- source/lobby/XmppClient.cpp
+++ source/lobby/XmppClient.cpp
@@ -370,12 +370,13 @@
 /**
  * Request the Connection data (ip, port...) from the server.
  */
-void XmppClient::SendIqGetConnectionData(const std::string& jid, const std::string& password)
+void XmppClient::SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP)
 {
 	glooxwrapper::JID targetJID(jid);
 
 	ConnectionData* connectionData = new ConnectionData();
 	connectionData->m_Password = password;
+	connectionData->m_UseSTUN = localIP ? "0" : "1";
 	glooxwrapper::IQ iq(gloox::IQ::Get, targetJID, m_client->getID());
 	iq.addExtension(connectionData);
 	m_connectionDataJid = iq.from().full();
@@ -1000,9 +1001,29 @@
 
 			glooxwrapper::IQ response(gloox::IQ::Result, iq.from(), iq.id());
 			ConnectionData* connectionData = new ConnectionData();
-			connectionData->m_Ip = g_NetServer->GetPublicIp();;
-			connectionData->m_Port = std::to_string(g_NetServer->GetPublicPort());
-			connectionData->m_UseSTUN = g_NetServer->GetUseSTUN() ? "true" : "";
+			if (cd->m_UseSTUN == "1")
+			{
+				connectionData->m_Ip = g_NetServer->GetPublicIp();
+				connectionData->m_Port = std::to_string(g_NetServer->GetPublicPort());
+				connectionData->m_UseSTUN = g_NetServer->GetUseSTUN() ? "true" : "";
+			}
+			else
+			{
+				CStr ip;
+				if (StunClient::FindLocalIP(ip))
+				{
+					connectionData->m_Ip = ip;
+					connectionData->m_Port = std::to_string(g_NetServer->GetPublicPort());
+					connectionData->m_UseSTUN = "";
+				}
+				else
+				{
+					LOGMESSAGE("Failed to get the local IP");
+					connectionData->m_Error = "not_server";
+				}
+				// Debug, remove before committing.
+				LOGWARNING("local IP %s", ip);
+			}
 
 			response.addExtension(connectionData);
 
Index: source/network/NetClient.cpp
===================================================================
--- source/network/NetClient.cpp
+++ source/network/NetClient.cpp
@@ -259,7 +259,8 @@
 		}
 
 		StunClient::StunEndpoint stunEndpoint;
-		if (!StunClient::FindStunEndpointJoin(*enetClient, stunEndpoint))
+		CStr ip;
+		if (!StunClient::FindStunEndpointJoin(*enetClient, stunEndpoint, ip))
 		{
 			PushGuiMessage(
 				"type", "netstatus",
@@ -268,6 +269,16 @@
 			return false;
 		}
 
+		// If the host is on the same network, we risk failing to connect
+		// on routers that don't support NAT hairpinning/NAT loopback.
+		// To work around that, send again a connection data request, but for internal IP this time.
+		if (ip == m_ServerAddress)
+		{
+			g_XmppClient->SendIqGetConnectionData(m_HostJID, m_Password, true);
+			// Return true anyways - we're on a success path here.
+			return true;
+		}
+
 		g_XmppClient->SendStunEndpointToHost(stunEndpoint, hostJID);
 
 		SDL_Delay(1000);
Index: source/network/StunClient.h
===================================================================
--- source/network/StunClient.h
+++ source/network/StunClient.h
@@ -37,9 +37,15 @@
 
 bool FindStunEndpointHost(CStr8& ip, u16& port);
 
-bool FindStunEndpointJoin(ENetHost& transactionHost, StunClient::StunEndpoint& stunEndpoint);
+bool FindStunEndpointJoin(ENetHost& transactionHost, StunClient::StunEndpoint& stunEndpoint, CStr8& ip);
 
 void SendHolePunchingMessages(ENetHost& enetClient, const std::string& serverAddress, u16 serverPort);
+
+/**
+ * Return the local IP.
+ * Technically not a STUN method, but convenient to define here.
+ */
+bool FindLocalIP(CStr8& ip);
 }
 
 #endif // STUNCLIENT_H
Index: source/network/StunClient.cpp
===================================================================
--- source/network/StunClient.cpp
+++ source/network/StunClient.cpp
@@ -392,7 +392,7 @@
 	return result == 0;
 }
 
-bool StunClient::FindStunEndpointJoin(ENetHost& transactionHost, StunClient::StunEndpoint& stunEndpoint)
+bool StunClient::FindStunEndpointJoin(ENetHost& transactionHost, StunClient::StunEndpoint& stunEndpoint, CStr8& ip)
 {
 	if (!STUNRequestAndResponse(transactionHost))
 		return false;
@@ -403,6 +403,7 @@
 	addr.host = ntohl(m_IP);
 	enet_address_get_host_ip(&addr, ipStr, ARRAY_SIZE(ipStr));
 
+	ip = ipStr;
 	stunEndpoint.ip = m_IP;
 	stunEndpoint.port = m_Port;
 
@@ -426,3 +427,47 @@
 		usleep(delay * 1000);
 	}
 }
+
+bool StunClient::FindLocalIP(CStr8& ip)
+{
+	int sock = socket(PF_INET, SOCK_DGRAM, 0);
+	sockaddr_in loopback;
+
+	if (sock == -1)
+	{
+		LOGERROR("Could not socket");
+		return false;
+	}
+
+	memset(&loopback, 0, sizeof(loopback));
+	loopback.sin_family = AF_INET;
+	loopback.sin_addr.s_addr = 1337;   // can be any IP address
+	loopback.sin_port = htons(9);      // using debug port
+
+	if (connect(sock, reinterpret_cast<sockaddr*>(&loopback), sizeof(loopback)) == -1)
+	{
+		close(sock);
+		LOGERROR("Could not connect");
+		return false;
+	}
+
+	socklen_t addrlen = sizeof(loopback);
+	if (getsockname(sock, reinterpret_cast<sockaddr*>(&loopback), &addrlen) == -1)
+	{
+		close(sock);
+		LOGERROR("Could not getsockname");
+		return false;
+	}
+
+	close(sock);
+
+	char buf[INET_ADDRSTRLEN];
+	if (inet_ntop(AF_INET, &loopback.sin_addr, buf, INET_ADDRSTRLEN) == 0)
+	{
+		LOGERROR("Could not inet_ntop");
+		return false;
+	}
+	ip = buf;
+
+	return true;
+}
Index: source/network/scripting/JSInterface_Network.cpp
===================================================================
--- source/network/scripting/JSInterface_Network.cpp
+++ source/network/scripting/JSInterface_Network.cpp
@@ -190,7 +190,7 @@
 	g_NetClient->SetUserName(playerName);
 	g_NetClient->SetHostJID(hostJID);
 	g_NetClient->SetGamePassword(hashedPass);
-	g_XmppClient->SendIqGetConnectionData(hostJID, hashedPass.c_str());
+	g_XmppClient->SendIqGetConnectionData(hostJID, hashedPass.c_str(), false);
 }
 
 void DisconnectNetworkGame()