diff --git a/daemon/HTTPServer.cpp b/daemon/HTTPServer.cpp
index 2a083dea..d236ca3d 100644
--- a/daemon/HTTPServer.cpp
+++ b/daemon/HTTPServer.cpp
@@ -222,7 +222,7 @@ namespace http {
 		s << "<b>" << tr("ERROR") << ":</b>&nbsp;" << string << "<br>\r\n";
 	}
 
-	static void ShowNetworkStatus (std::stringstream& s, RouterStatus status)
+	static void ShowNetworkStatus (std::stringstream& s, RouterStatus status, RouterError error)
 	{
 		switch (status)
 		{
@@ -235,7 +235,7 @@ namespace http {
 			case eRouterStatusError:
 			{
 				s << tr("Error");
-				switch (i2p::context.GetError ())
+				switch (error)
 				{
 					case eRouterErrorClockSkew:
 						s << " - " << tr("Clock skew");
@@ -260,12 +260,12 @@ namespace http {
 		ShowUptime(s, i2p::context.GetUptime ());
 		s << "<br>\r\n";
 		s << "<b>" << tr("Network status") << ":</b> ";
-		ShowNetworkStatus (s, i2p::context.GetStatus ());
+		ShowNetworkStatus (s, i2p::context.GetStatus (), i2p::context.GetError ());
 		s << "<br>\r\n";
 		if (i2p::context.SupportsV6 ())
 		{
 			s << "<b>" << tr("Network status v6") << ":</b> ";
-			ShowNetworkStatus (s, i2p::context.GetStatusV6 ());
+			ShowNetworkStatus (s, i2p::context.GetStatusV6 (), i2p::context.GetErrorV6 ());
 			s << "<br>\r\n";
 		}
 #if ((!defined(WIN32) && !defined(QT_GUI_LIB) && !defined(ANDROID)) || defined(ANDROID_BINARY))
diff --git a/libi2pd/RouterContext.cpp b/libi2pd/RouterContext.cpp
index 636d47ce..2095a465 100644
--- a/libi2pd/RouterContext.cpp
+++ b/libi2pd/RouterContext.cpp
@@ -29,7 +29,7 @@ namespace i2p
 	RouterContext::RouterContext ():
 		m_LastUpdateTime (0), m_AcceptsTunnels (true), m_IsFloodfill (false),
 		m_ShareRatio (100), m_Status (eRouterStatusUnknown), m_StatusV6 (eRouterStatusUnknown),
-		m_Error (eRouterErrorNone), m_NetID (I2PD_NET_ID)
+		m_Error (eRouterErrorNone), m_ErrorV6 (eRouterErrorNone), m_NetID (I2PD_NET_ID)
 	{
 	}
 
@@ -263,6 +263,7 @@ namespace i2p
 		if (status != m_StatusV6)
 		{
 			m_StatusV6 = status;
+			m_ErrorV6 = eRouterErrorNone;
 			switch (m_StatusV6)
 			{
 				case eRouterStatusOK:
diff --git a/libi2pd/RouterContext.h b/libi2pd/RouterContext.h
index 4946b7ca..9e02b5d5 100644
--- a/libi2pd/RouterContext.h
+++ b/libi2pd/RouterContext.h
@@ -109,6 +109,8 @@ namespace garlic
 			RouterStatus GetStatusV6 () const { return m_StatusV6; };
 			void SetStatusV6 (RouterStatus status);
 			void SetStatusV6SSU2 (RouterStatus status);
+			RouterError GetErrorV6 () const { return m_ErrorV6; };
+			void SetErrorV6 (RouterError error) { m_StatusV6 = eRouterStatusError; m_ErrorV6 = error; };
 			int GetNetID () const { return m_NetID; };
 			void SetNetID (int netID) { m_NetID = netID; };
 			bool DecryptTunnelBuildRecord (const uint8_t * encrypted, uint8_t * data);
@@ -197,7 +199,7 @@ namespace garlic
 			uint64_t m_BandwidthLimit; // allowed bandwidth
 			int m_ShareRatio;
 			RouterStatus m_Status, m_StatusV6;
-			RouterError m_Error;
+			RouterError m_Error, m_ErrorV6;
 			int m_NetID;
 			std::mutex m_GarlicMutex;
 			std::unique_ptr<NTCP2PrivateKeys> m_NTCP2Keys;
diff --git a/libi2pd/SSU2.cpp b/libi2pd/SSU2.cpp
index 551dd148..e551010a 100644
--- a/libi2pd/SSU2.cpp
+++ b/libi2pd/SSU2.cpp
@@ -155,6 +155,14 @@ namespace transport
 		}
 		return false;
 	}	
+
+	uint16_t SSU2Server::GetPort (bool v4) const
+	{
+		boost::system::error_code ec;
+		boost::asio::ip::udp::endpoint ep = v4 ? m_SocketV4.local_endpoint (ec) : m_SocketV6.local_endpoint (ec);
+		if (ec) return 0;
+		return ep.port ();
+	}	
 		
 	boost::asio::ip::udp::socket& SSU2Server::OpenSocket (const boost::asio::ip::udp::endpoint& localEndpoint)
 	{
diff --git a/libi2pd/SSU2.h b/libi2pd/SSU2.h
index 010c2c00..00e944e4 100644
--- a/libi2pd/SSU2.h
+++ b/libi2pd/SSU2.h
@@ -55,6 +55,7 @@ namespace transport
 			boost::asio::io_service& GetService () { return GetIOService (); };
 			void SetLocalAddress (const boost::asio::ip::address& localAddress);
 			bool IsSupported (const boost::asio::ip::address& addr) const;
+			uint16_t GetPort (bool v4) const;
 		
 			void AddSession (std::shared_ptr<SSU2Session> session);
 			void RemoveSession (uint64_t connID);
diff --git a/libi2pd/SSU2Session.cpp b/libi2pd/SSU2Session.cpp
index 475d7cef..e463e6fc 100644
--- a/libi2pd/SSU2Session.cpp
+++ b/libi2pd/SSU2Session.cpp
@@ -1370,16 +1370,9 @@ namespace transport
 					HandleAck (buf + offset, size);
 				break;
 				case eSSU2BlkAddress:
-				{
-					boost::asio::ip::udp::endpoint ep;
-					if (ExtractEndpoint (buf + offset, size, ep))
-					{		
-						LogPrint (eLogInfo, "SSU2: Our external address is ", ep);
-						if (!i2p::util::net::IsInReservedRange (ep.address ()))
-							i2p::context.UpdateAddress (ep.address ());
-					}	
-					break;
-				}
+					LogPrint (eLogDebug, "SSU2: Address");
+					HandleAddress (buf + offset, size);
+				break;
 				case eSSU2BlkIntroKey:
 				break;
 				case eSSU2BlkRelayTagRequest:
@@ -1482,6 +1475,47 @@ namespace transport
 		}	
 	}
 
+	void SSU2Session::HandleAddress (const uint8_t * buf, size_t len)
+	{
+		boost::asio::ip::udp::endpoint ep;
+		if (ExtractEndpoint (buf, len, ep))
+		{		
+			LogPrint (eLogInfo, "SSU2: Our external address is ", ep);
+			if (!i2p::util::net::IsInReservedRange (ep.address ()))
+			{	
+				i2p::context.UpdateAddress (ep.address ());
+				// check our port
+				bool isV4 = ep.address ().is_v4 ();
+				if (ep.port () != m_Server.GetPort (isV4))
+				{
+					if (isV4)
+					{
+						if (i2p::context.GetStatus () == eRouterStatusTesting)
+							i2p::context.SetError (eRouterErrorSymmetricNAT);
+					}	
+					else
+					{
+						if (i2p::context.GetStatusV6 () == eRouterStatusTesting)
+							i2p::context.SetErrorV6 (eRouterErrorSymmetricNAT);
+					}						
+ 				}	
+				else
+				{
+					if (isV4)
+					{
+						if (i2p::context.GetStatus () == eRouterStatusError && i2p::context.GetError () == eRouterErrorSymmetricNAT)
+							i2p::context.SetStatus (eRouterStatusTesting);
+					}	
+					else
+					{
+						if (i2p::context.GetStatusV6 () == eRouterStatusError && i2p::context.GetErrorV6 () == eRouterErrorSymmetricNAT)
+							i2p::context.SetStatusV6 (eRouterStatusTesting);
+					}		
+				}	
+			}	
+		}	
+	}	
+		
 	void SSU2Session::HandleFirstFragment (const uint8_t * buf, size_t len)
 	{
 		uint32_t msgID; memcpy (&msgID, buf + 1, 4);
diff --git a/libi2pd/SSU2Session.h b/libi2pd/SSU2Session.h
index 3971358c..eae593c2 100644
--- a/libi2pd/SSU2Session.h
+++ b/libi2pd/SSU2Session.h
@@ -278,6 +278,7 @@ namespace transport
 			void HandlePayload (const uint8_t * buf, size_t len);
 			void HandleAck (const uint8_t * buf, size_t len);
 			void HandleAckRange (uint32_t firstPacketNum, uint32_t lastPacketNum, uint64_t ts);
+			void HandleAddress (const uint8_t * buf, size_t len);
 			bool ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep);
 			size_t CreateEndpoint (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& ep);
 			std::shared_ptr<const i2p::data::RouterInfo::Address> FindLocalAddress () const;