Neigbhour stuck in Idle

[Nykomling]

I have a BGP neighbour that dont come up

its stuck in Idle

and im clueless how to troubleshoot it

äny good tips?

[Toshi_Esumi]

Firstly you can sniff BGP traffic between neighbors at TCP 179 on the intended interface. Many issues with BGP come from reachability problems if all other BGP config seems to be correct.

[Nykomling]

I inherited this site and without documentation...

We have about 32 devices that works  and now 33,34 and 35  just stays in Idle compared config from working ones cant see anyhing thats diffrent more than the IP...

[emnoc]

You do not need documentation to trouble that and idle means exactly that

1: is the interface up

2: if you or the peer telnet to port 179 do you get a connect 

3: we are assuming this a fortigate "diag sniffer packet any 'host x.x.x.x and port 179' do you see traffic 

I be you 10 out of 10, you have no route to that network and that bgp peer is not locally connected. It one or both.  

Ken Felix