I am trying to configure BGP between 2 routers, but for some reason I am not getting routes from other end. I have configured everything at both ends including no sync and no auto-summary. My neighborship is also getting successfully built. But for some reason I am not getting routes. but whenever I am adding "ip route x.x.0.0 255.255.0.0 Null0" this command I am immediately getting all routes.
Please need urgent help.
Thanks and regards,
This is in fact because the prefixes you are trying to advertise were not installed in the IP routing table. In order to do so, you should add those static routes pointing to null0 with high Administrative distance to eleminate your router dropping the Packets destined for those Prefixes. Or You dont have to do so if and ONLY if the routes are directly connected.
Synchronization has nothing to do with that in any case. Synchronization rule stays: "a BGP Speaker shall not advertise any BGP learned routes to any EBGP neighbor unless the routes are validated by the IGP".
No auto-summary has also nothing to do with that, The auto-summary command Only affects redistributed routes into BGP.
I hope I am informative.
the BGP next-hop must be known or the BGP advertisement is not installed
if using no auto-summary the network command in BGP needs to match the real ip subnet
router bgp XX
look in routing tabel for 192.168.2.0/24 (major network boundary)
router bgp XX
network 192.168.3.0 255.255.255.128
BGP looks for 192.168.2.0/25 and advertises it if it founds in routing table
so depending on the usage of a subnet of a major subnet and/or auto-summary settings you may need a network command with a mask
for sure you haven't placed a /16 on an interface but a subnet of this /16.
then you may use an aggregate command with summary-only to have only the /16 advertised.
Hope to help