Exploring the BGP Neighbor CONNECT State

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…