One of our customers complained that they did not receive several prefixes from our router / their BGP peer, but they received the prefixes from others (ISP). I had to go to check this routing table in our router.
When I checked the prefixes in our router, it said that the BGP next-hop is inaccessible meaning that our router could not ping to the next-hop IP address for the prefixes.
core-jkt# sh ip bgp 103.6.1xx.2 BGP routing table entry for 103.6.1xx.0/24 Paths: (1 available, no best path) Not advertised to any peer 246xx 1321xx 58.65.2xx.51 (inaccessible) from 203.81.1xx.246 (58.65.2xx.13) Origin IGP, localpref 10, valid, internal Community: 245xx:300 Last update: Thu Jan 2 21:10:39 2014
Since the IP address 58.65.2xx.51 is coming from 203.81.1xx.246 peer, I need to add a static route as below:
In Linux
route add -host 58.65.2xx.51 gw 203.81.1xx.246
In Cisco
ip route 58.65.2xx.51 255.255.255.255 203.81.1xx.246
Now check again the BGP routing table for the prefixes. It is now accessible and working well.
core-jkt# sh ip bgp 103.6.1xx.2 BGP routing table entry for 103.6.1xx.0/24 Paths: (1 available, best #1, table Default-IP-Routing-Table) Advertised to non peer-group peers: 42.62.1xx.1 103.14.xx.22 103.246.1xx.254 246xx 1321xx 58.65.2xx.51 from 203.81.1xx.246 (58.65.2xx.13) Origin IGP, localpref 10, valid, internal, best Community: 245xx:300 Last update: Thu Jan 2 21:10:40 2014
Verify to ask the customer to check the status.