Index: source/lobby/IXmppClient.h
===================================================================
--- source/lobby/IXmppClient.h
+++ source/lobby/IXmppClient.h
@@ -36,7 +36,7 @@
 	virtual void SendIqGetProfile(const std::string& player) = 0;
 	virtual void SendIqGameReport(const ScriptRequest& rq, JS::HandleValue data) = 0;
 	virtual void SendIqRegisterGame(const ScriptRequest& rq, JS::HandleValue data) = 0;
-	virtual void SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP) = 0;
+	virtual void SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP, const std::string& myIP = "", u16 myPort = 0) = 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 ScriptRequest& rq, JS::HandleValue data);
 	void SendIqRegisterGame(const ScriptRequest& rq, JS::HandleValue data);
-	void SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP);
+	void SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP, const std::string& myIP, u16 myPort);
 	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
@@ -365,13 +365,15 @@
 /**
  * Request the Connection data (ip, port...) from the server.
  */
-void XmppClient::SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP)
+void XmppClient::SendIqGetConnectionData(const std::string& jid, const std::string& password, bool localIP, const std::string& myIP, u16 myPort)
 {
 	glooxwrapper::JID targetJID(jid);
 
 	ConnectionData* connectionData = new ConnectionData();
 	connectionData->m_Password = password;
 	connectionData->m_IsLocalIP = localIP ? "1" : "0";
+	connectionData->m_Ip = myIP;
+	connectionData->m_Port = std::to_string(myPort);
 	glooxwrapper::IQ iq(gloox::IQ::Get, targetJID, m_client->getID());
 	iq.addExtension(connectionData);
 	m_connectionDataJid = iq.from().full();
@@ -986,10 +988,18 @@
 				return true;
 			}
 
+			// If the client forwarded its IP, attempt hole-punching.
+			CStr clientIP = cd->m_Ip.to_string();
+			if (!clientIP.empty())
+			{
+				LOGWARNING("punching hole to %s", clientIP);
+				g_NetServer->SendHolePunchingMessage(clientIP, std::strtol(cd->m_Port.to_string().c_str(), nullptr, 10));
+			}
+
 			glooxwrapper::IQ response(gloox::IQ::Result, iq.from(), iq.id());
 			ConnectionData* connectionData = new ConnectionData();
 
-			if (cd->m_IsLocalIP.to_string() == "0")
+			if (cd->m_IsLocalIP.to_string() == "0" && clientIP != g_NetServer->GetPublicIp())
 			{
 				connectionData->m_Ip = g_NetServer->GetPublicIp();
 				connectionData->m_Port = std::to_string(g_NetServer->GetPublicPort());
Index: source/network/NetClient.h
===================================================================
--- source/network/NetClient.h
+++ source/network/NetClient.h
@@ -125,6 +125,11 @@
 	 */
 	bool SetupConnection(ENetHost* enetClient);
 
+	/**
+	 * Send a request for server connection data via the lobby.
+	 */
+	bool SetupConnectionViaLobby(const CStr& hostJID, bool localIP);
+
 	/**
 	 * Connect to the remote networked server using lobby.
 	 * Push netstatus messages on failure.
Index: source/network/NetClient.cpp
===================================================================
--- source/network/NetClient.cpp
+++ source/network/NetClient.cpp
@@ -195,22 +195,53 @@
 
 bool CNetClient::SetupConnection(ENetHost* enetClient)
 {
-	CNetClientSession* session = new CNetClientSession(*this);
-	bool ok = session->Connect(m_ServerAddress, m_ServerPort, enetClient);
-	SetAndOwnSession(session);
+	bool ok = false;
+	if (m_Session)
+	{
+		ok = m_Session->Connect(m_ServerAddress, m_ServerPort, nullptr);
+	}
+	else
+	{
+		CNetClientSession* session = new CNetClientSession(*this);
+		ok = session->Connect(m_ServerAddress, m_ServerPort, enetClient);
+		SetAndOwnSession(session);
+	}
 	m_PollingThread = std::thread(Threading::HandleExceptions<CNetClientSession::RunNetLoop>::Wrapper, m_Session);
 	return ok;
 }
 
 void CNetClient::SetupServerData(CStr address, u16 port, bool stun)
 {
-	ENSURE(!m_Session);
-
 	m_ServerAddress = address;
 	m_ServerPort = port;
 	m_UseSTUN = stun;
 }
 
+bool CNetClient::SetupConnectionViaLobby(const CStr& hostJID, bool localIP)
+{
+	if (!g_XmppClient)
+		return false;
+	m_UseSTUN = true;
+	m_HostJID = hostJID;
+
+	ENetAddress hostAddr{ ENET_HOST_ANY, ENET_PORT_ANY };
+	ENetHost* enetClient = enet_host_create(&hostAddr, 1, 1, 0, 0);
+	CStr ip;
+	u16 port;
+	if (!StunClient::FindPublicIP(*enetClient, ip, port))
+	{
+		enet_host_destroy(enetClient);
+		return false;
+	}
+
+	CNetClientSession* session = new CNetClientSession(*this, enetClient);
+	SetAndOwnSession(session);
+
+	LOGWARNING("NetClient: found external address at %s:%i", ip.c_str(), port);
+	g_XmppClient->SendIqGetConnectionData(m_HostJID, m_Password, localIP, ip, port);
+	return true;
+}
+
 void CNetClient::HandleGetServerDataFailed(const CStr& error)
 {
 	if (m_Session)
@@ -225,9 +256,6 @@
 
 bool CNetClient::TryToConnect(const CStr& hostJID)
 {
-	if (m_Session)
-		return false;
-
 	if (m_ServerAddress.empty())
 	{
 		PushGuiMessage(
@@ -238,7 +266,7 @@
 	}
 
 	ENetHost* enetClient = nullptr;
-	if (g_XmppClient && m_UseSTUN)
+	if (false && g_XmppClient && m_UseSTUN)
 	{
 		ENetAddress hostAddr{ ENET_HOST_ANY, ENET_PORT_ANY };
 		enetClient = enet_host_create(&hostAddr, 1, 1, 0, 0);
@@ -276,10 +304,10 @@
 		g_XmppClient->SendStunEndpointToHost(ip, port, hostJID);
 
 		SDL_Delay(1000);
-
-		StunClient::SendHolePunchingMessages(*enetClient, m_ServerAddress, m_ServerPort);
 	}
 
+	StunClient::SendHolePunchingMessages(*enetClient, m_ServerAddress, m_ServerPort);
+
 	if (!g_NetClient->SetupConnection(enetClient))
 	{
 		PushGuiMessage(
Index: source/network/NetSession.h
===================================================================
--- source/network/NetSession.h
+++ source/network/NetSession.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2020 Wildfire Games.
+/* Copyright (C) 2021 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -70,6 +70,7 @@
 
 public:
 	CNetClientSession(CNetClient& client);
+	CNetClientSession(CNetClient& client, ENetHost* enetClient);
 	~CNetClientSession();
 
 	bool Connect(const CStr& server, const u16 port, ENetHost* enetClient);
Index: source/network/NetSession.cpp
===================================================================
--- source/network/NetSession.cpp
+++ source/network/NetSession.cpp
@@ -37,6 +37,11 @@
 {
 }
 
+CNetClientSession::CNetClientSession(CNetClient& client, ENetHost* enetClient) : CNetClientSession(client)
+{
+	m_Host = enetClient;
+}
+
 CNetClientSession::~CNetClientSession()
 {
 	ENSURE(!m_LoopRunning);
@@ -57,18 +62,26 @@
 bool CNetClientSession::Connect(const CStr& server, const u16 port, ENetHost* enetClient)
 {
 	ENSURE(!m_LoopRunning);
-	ENSURE(!m_Host);
 	ENSURE(!m_Server);
 
-	// Create ENet host
-	ENetHost* host;
-	if (enetClient != nullptr)
-		host = enetClient;
+	if (m_Host)
+	{
+		// Cannot pass a client if we already have a host: code logic error.
+		ENSURE(!enetClient);
+	}
 	else
-		host = enet_host_create(NULL, 1, CHANNEL_COUNT, 0, 0);
+	{
+		// Create ENet host
+		ENetHost* host;
+		if (enetClient != nullptr)
+			host = enetClient;
+		else
+			host = enet_host_create(NULL, 1, CHANNEL_COUNT, 0, 0);
 
-	if (!host)
-		return false;
+		if (!host)
+			return false;
+		m_Host = host;
+	}
 
 	// Bind to specified host
 	ENetAddress addr;
@@ -77,11 +90,10 @@
 		return false;
 
 	// Initiate connection to server
-	ENetPeer* peer = enet_host_connect(host, &addr, CHANNEL_COUNT, 0);
+	ENetPeer* peer = enet_host_connect(m_Host, &addr, CHANNEL_COUNT, 0);
 	if (!peer)
 		return false;
 
-	m_Host = host;
 	m_Server = peer;
 
 	m_Stats = new CNetStatsTable(m_Server);
Index: source/network/scripting/JSInterface_Network.cpp
===================================================================
--- source/network/scripting/JSInterface_Network.cpp
+++ source/network/scripting/JSInterface_Network.cpp
@@ -186,7 +186,7 @@
 	g_NetClient->SetUserName(playerName);
 	g_NetClient->SetHostJID(hostJID);
 	g_NetClient->SetGamePassword(hashedPass);
-	g_XmppClient->SendIqGetConnectionData(hostJID, hashedPass.c_str(), false);
+	g_NetClient->SetupConnectionViaLobby(hostJID, false);
 }
 
 void DisconnectNetworkGame()