dear all, finally, stop the iptables. 2 BIRD routers can establish BGP. But cannot form BGP with Cisco csr1000v router Last error: Socket: Connection refused <-- 1. can traceroute from cisco router to a BIRD 2. cannot traceroute from the BIRD router to the Cisco router 3. can ping together 4. iptables service is stopped on BIRD Would you please help.