04-10-2024 01:19 AM
Hello,
R1 is connected to R2 and uses BGP.
R1 sends prefixes to R2 with community 100:100.
On R2 I receive the prefix via BGP with the correct community : sh ip bgp 192.168.1.111 => Community: 100:100
Now I would like to send only prefixes with community 100:100 to the BGP R3 peer connected to R2.
It does not work, here the conf of R2 :
router bgp 100
bgp router-id 10.10.10.2
neighbor 10.10.10.1 remote-as 100
neighbor 10.10.10.1 description * R1 *
neighbor 10.10.10.3 remote-as 100
neighbor 10.10.10.3 description * R3 *
!
address-family ipv4
neighbor 10.10.10.1 activate
neighbor 10.10.10.1 soft-reconfiguration inbound
neighbor 10.10.10.3 activate
neighbor 10.10.10.3 send-community both
neighbor 10.10.10.3 soft-reconfiguration inbound
neighbor 10.10.10.3 route-map TO-R3 out
exit-address-family
!
ip bgp-community new-format
ip community-list 1 permit 100:100
!
route-map TO-R3 permit 10
match community 1
set local-preference 500
set origin igp
!
route-map TO-R3 deny 20
The route-map does not match prefixes with community 100:100, why ?
Thanks
Solved! Go to Solution.
04-10-2024 01:54 AM
You use ibgp and ibgp peer never readvertise prefix to other ibgp neighbors.
You need to use ebgp or config RR
MHM
04-10-2024 01:42 AM
Seems like your config should work as intended. Have you cleared the BGP peering?
04-10-2024 01:51 AM
Yes, on R2 I have try clear ip bgp *
192.168.1.111 is not announced at R3...
04-10-2024 01:54 AM
You use ibgp and ibgp peer never readvertise prefix to other ibgp neighbors.
You need to use ebgp or config RR
MHM
04-10-2024 01:59 AM
It seems like there might be a misconfiguration in your route-map.
By using the "match extcommunity" statement instead of "match community", you should be able to match prefixes with the community 100:100. So, the corrected configuration would look like this:
route-map TO-R3 permit 10
match extcommunity 1
set local-preference 500
set origin igp
route-map TO-R3 deny 20
04-10-2024 04:52 AM
I'm going to use RR !
Thank you for the feedback.
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