BGP ebgp-multihop

[Maurice Ball]

I have configured a test lab with BGP. I have two different AS setup with dual connections between the systems. I configured the loopbacks and update-source between the AS but BGP did not become active until I changed the ebgp-multihop count from default and set hop count to 2. My question is, is there a troubleshooting command I can use that will show me that the ebgp-multihop is not set correctly.

[Peter Paluch · Accepted solution]

Hello Maurice,

If the ebgp-multihop is missing for an indirectly-connected eBGP neighbor, at the bottom of the show ip bgp neighbor X.X.X.X you will find these lines:

[ ... cut ... ]

  Connections established 0; dropped 0

  Last reset never

  External BGP neighbor not directly connected.

  No active TCP connection

There is the indication of the eBGP peer not being directly connected.

You may also be interested in reading the following thread about the ebgp-multihop and disable-connected-check that can be used specifically for loopback peerings between directly connected eBGP neighbors like yours.

https://supportforums.cisco.com/message/3571118#3571118

Best regards,

Peter

[Maurice Ball]

Thanks I really appreciate the help.

Sent from Cisco Technical Support iPhone App

[Peter Paluch]

Hello Maurice,

You are welcome!

Best regards,

Peter