diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 094cfdc..89d6dc0 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1319,6 +1319,7 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
 			tsk->conn_type = dest->addr.name.name.type;
 			tsk->conn_instance = dest->addr.name.name.instance;
 		}
+		msg_set_syn(hdr, 1);
 	}
 
 	seq = &dest->addr.nameseq;
@@ -1478,6 +1479,7 @@ static void tipc_sk_finish_conn(struct tipc_sock *tsk, u32 peer_port,
 	struct net *net = sock_net(sk);
 	struct tipc_msg *msg = &tsk->phdr;
 
+	msg_set_syn(msg, 0);
 	msg_set_destnode(msg, peer_node);
 	msg_set_destport(msg, peer_port);
 	msg_set_type(msg, TIPC_CONN_MSG);
@@ -2006,6 +2008,9 @@ static bool tipc_sk_filter_connect(struct tipc_sock *tsk, struct sk_buff *skb)
 		return false;
 	case TIPC_LISTEN:
 		/* Accept only SYN message */
+		if (!msg_is_syn(hdr) &&
+		    tipc_node_get_capabilities(net, onode) & TIPC_SYN_BIT)
+			return false;
 		if (!con_msg && !err)
 			return true;
 		return false;