diff --git a/src/vnet/session/transport.c b/src/vnet/session/transport.c
index 06954c0..7e40164 100644
--- a/src/vnet/session/transport.c
+++ b/src/vnet/session/transport.c
@@ -734,7 +734,18 @@
       port = clib_net_to_host_u16 (rmt_cfg->peer.port);
       *lcl_port = port;
 
-      return transport_endpoint_mark_used (proto, lcl_addr, port);
+      if (!transport_endpoint_mark_used (proto, lcl_addr, port))
+	return 0;
+
+      /* IP:port pair already in use, check if 6-tuple available */
+      if (session_lookup_connection (rmt->fib_index, lcl_addr, &rmt->ip, port,
+				     rmt->port, proto, rmt->is_ip4))
+	return SESSION_E_PORTINUSE;
+
+      /* 6-tuple is available so increment lcl endpoint refcount */
+      transport_share_local_endpoint (proto, lcl_addr, port);
+
+      return 0;
     }
 
   return 0;
diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index 6e0c147..5c612a7 100644
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -808,8 +808,8 @@
       || (!rmt->is_ip4 && vec_len (tcp_cfg.ip6_src_addrs)))
     rv = tcp_alloc_custom_local_endpoint (&lcl_addr, &lcl_port, rmt);
   else
-    rv = transport_alloc_local_endpoint (TRANSPORT_PROTO_TCP,
-					 rmt, &lcl_addr, &lcl_port);
+    rv = transport_alloc_local_endpoint (TRANSPORT_PROTO_TCP, rmt, &lcl_addr,
+					 &lcl_port);
 
   if (rv)
     return rv;