Exabgp and fastnetmon question

RouterOS Forwarding Protocols
1

Hello,
we have configured fastnetmon and exabgp and we have set exabgp announce whole subnet to our core routers, because in our datacenter only one of our upstreams has Blackhole server so we should first tag whole /24 with a community and then blackhole related /32 with another community.
when i have enabled whole subnet announcements in exabgp and FNM then exabgp announce whole supernet and i need it only announce /24 , for better understanding this is fnm/exabgp log:


exabgp: 13951 processes Command from process service-dynamic : announce route 192.168.22.0/22 next-hop 192.168.134.234 community 65001:666
exabgp: 13951 processes Command from process service-dynamic : announce route 192.168.22.229/32 next-hop 192.168.134.234 community 65001:666
exabgp: 13951 reactor Route added to neighbor 192.168.134.233 local-ip 192.168.134.234 local-as 65001 peer-as 65001 router-id 192.168.134.234 family-allowed in-open : 192.168.22.0/22 next-hop 192.168.134.234 community 65001:666
exabgp: 13951 reactor Route added to neighbor 192.168.134.233 local-ip 192.168.134.234 local-as 65001 peer-as 65001 router-id 192.168.134.234 family-allowed in-open : 192.168.22.229/32 next-hop 192.168.134.234 community 65001:666
exabgp: 13951 reactor Performing dynamic route update
exabgp: 13951 reactor Updated peers dynamic routes successfully

if you see it is announcing whole /22 however i am announcing all of my prefixes in /24 format so i need exabgp announce only /24 format,
any idea?
thank you.

2

It’s not Exabgp, it’s fasnetmon, exabgp only publish what fastnetmon tells it to do.

Fastnetmon will publish the prefixes as seen in the configuration, depending on whether you use the community or the standard version you’ll either need to edit it via the networks file or the cli respectively.

Either way, all you gotta do is de-aggregate the prefixes, in the case of a /22, instead of setting up the /22 as the network, use the individual /24.