Problem with BGP community out

[sebastien3]

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

[Torbjørn]

Seems like your config should work as intended. Have you cleared the BGP peering?

[sebastien3]

Yes, on R2 I have try clear ip bgp *

192.168.1.111 is not announced at R3...

[MHM Cisco World · Accepted solution]

You use ibgp and ibgp peer never readvertise prefix to other ibgp neighbors. 

You need to use ebgp or config RR

MHM

[Max Jobs]

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

[sebastien3]

I'm going to use RR !

Thank you for the feedback.