BGP between Cisco Nexus and Fortigate

It is not uncommon to find that different vendors have slightly different implementations when it comes to standards technologies that should work seamless.

I recently came across a BGP capability negotiation problem between a Nexus 7000 and a client Fortigate. Today’s post is not teaching about any new technologies, but instead showing the troubleshooting methodology I used to find the problem.

The setup is simple. A Nexus 7000 and a Fortigate connected via nexus layer2 hosting infrastructure, to peer with BGP.
At face value the eBGP session between Nexus 7000 and the Fortigate never came up:

N7K# sh ip bgp summary | i 10.5.0.20
Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.5.0.20   4 65123     190     190        0    0    0 0:12:30  Idle

The first steps should verify the obvious.

  •  Configuration! This check should included checking the ASNs, the peering IP addresses, source-interfaces and passwords matching.

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