Exploring the BGP Neighbor CONNECT State « ipSpace.net blog

Sakar left an interesting comment on my The Curious Case of the BGP Connect State blog post, claiming that Cisco IOS/XE goes through a CONNECT state when opening an incoming BGP session. I wanted to double-check this behavior, so I needed a scenario where one router would keep sending TCP SYN requests, the other would not (or we wouldn’t learn anything), and the two routers could not communicate (or they’d quickly go into the OPEN state). Here’s my first attempt at meeting those requirements:

Source: https://blog.ipspace.net/2026/08/exploring-bgp-connect-state. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.