diff --git a/libi2pd/NTCP2.cpp b/libi2pd/NTCP2.cpp
index 1e617a8a..ca6dc858 100644
--- a/libi2pd/NTCP2.cpp
+++ b/libi2pd/NTCP2.cpp
@@ -1055,7 +1055,12 @@ namespace transport
 		for (auto it: msgs)
 			m_SendQueue.push_back (it);
 		if (!m_IsSending) 
-			SendQueue ();		
+			SendQueue ();	
+		else if (m_SendQueue.size () > NTCP2_MAX_OUTGOING_QUEUE_SIZE)
+		{
+			LogPrint (eLogWarning, "NTCP2: outgoing messages queue size exceeds ", NTCP2_MAX_OUTGOING_QUEUE_SIZE);
+			Terminate ();
+		}	
 	}
 
 	void NTCP2Session::SendLocalRouterInfo ()
diff --git a/libi2pd/NTCP2.h b/libi2pd/NTCP2.h
index f11be500..7db6e8bf 100644
--- a/libi2pd/NTCP2.h
+++ b/libi2pd/NTCP2.h
@@ -39,6 +39,7 @@ namespace transport
 	const int NTCP2_TERMINATION_CHECK_TIMEOUT = 30; // 30 seconds
 
 	const int NTCP2_CLOCK_SKEW = 60; // in seconds	
+	const int NTCP2_MAX_OUTGOING_QUEUE_SIZE = 500; // how many messages we can queue up
 
 	enum NTCP2BlockType
 	{