I run a BGP session over an L2TP tunnel. Normally this works fine. Occasionally though, one end of the peer (the L2TP client end) will end up with the tunnel established, but the BGP peer stuck in 'open sent'.

When this happens, the only recourse is to bounce the BGP peer (disable/enable.) This peer exchanges just a handful of routes.

This has happened on 6.36; updated to 6.37.3 to see if this improves.

My current theory is that the session attempts to establish before the tunnel is up, and never times out.

Has anyone written a BGP watchdog script? I'd think something like checking if it's been in 'open sent' for a minute or two would be sufficient. Advice?