I am trying to understnad BGP messages and i configured bgp as below.
@@@@@@@@ A-End @@@@@@@
ip address 192.168.14.1 255.255.255.255
router bgp 9498
neighbor 172.16.16.1 remote-as 64520
neighbor 172.16.16.1 update-source Loopback100
ip route 172.16.16.1 255.255.255.255 10.10.10.2
@@@@@@@@ B-End @@@@@@@
ip address 172.16.16.1 255.255.255.255
router bgp 64520
neighbor 192.168.14.1 remote-as 9498
neighbor 192.168.14.1 ebgp-multihop 3
neighbor 192.168.14.1 update-source Loopback100
ip route 192.168.14.1 255.255.255.255 10.10.10.1
I purposefully removed ebgp-multihop 3 command from A-end and bgp is not coming up as expected. I have also captured wireshark and i can see that B end is sending TCP packet and A end is sending RST message. I just what to know how A end is sending reset, I mean what is it verifying. I tried to run bgp debug but only getting below message which is misleading. Is there any way to see how router at A end is decided to send TCP RST message.
*Feb 23 18:04:19.811: BGP: 172.16.16.1 active open failed - no route to peer, open active delayed 10240ms (35000ms max, 60% jitter)
Please let me know if my query is confusing.
A wonderful observation! Yes, I was somewhat vague. In fact, for eBGP peers, the ebgp-multihop 1 is the default and entering it explicitly does not change anything because this setting is already present, albeit implicitly. Very good point indeed!
Thank you - I rephrase my statement as follows:
This "directly connected check" is performed for all eBGP peers having either ebgp-multihop 1 or no ebgp-multihop configured. If ebgp-multihop 2 or more is configured for a neighbor, this check is not performed.
Would you agree with this formulation?