Created On 02/08/19 00:06 AM - Last Updated 02/08/19 00:06 AM
Mobile Network Infrastructure
This article focuses on explaining the meaning of 'error subcode 5 (Connection rejected)' while establishing BGP between two firewalls.
Excerpt from RFC:
If a BGP speaker decides to disallow a BGP connection (e.g., the peer
is not configured locally) after the speaker accepts a transport
protocol connection, then the BGP speaker SHOULD send a NOTIFICATION
message with the Error Code Cease and the Error Subcode "Connection
This means that after initial TCP handshake between the BGP peers, when peer A receives a OPEN message from peer B, and peer A does not recognize peer B, it would send Notification message with Subcode "Connection Rejected"
Assume following topology:
PA-1 (192.168.30.1) ----- (192.168.30.2) PA-2
PA-2 has a misconfigured peer IP address: (instead of 192.168.30.1 it is configured as 192.168.30.3)
As soon as PA-2 (192.168.30.2) receives a OPEN message from PA-1, it sends a Notification message:
PA-1 shows this notification message being received and error code in routed.log:
Edit the configuration to include correct peer IP address on the firewall.