Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

BGP not advertising a particular subnet


Please refer to the following configuration. I want to know why the subnet is not advertised out.

router bgp aaaaa

no synchronization

no bgp log-neighbor-changes

network mask

network mask

network mask

network mask

network mask

neighbor remote-as 4773

neighbor route-map AS-PREPEND out

no auto-summary


route-map AS-PREPEND permit 10

match ip address prefix-list prependlist

set as-path prepend aaaaa


route-map AS-PREPEND permit 20


ip prefix-list prependlist seq 5 permit



Router> sh ip bgp ne ad

BGP table version is 8389, local router ID is

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale

Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path

*> 30720 32768 i

*> 30720 32768 i

*> 30720 32768 i

*> 0 32768 i


Router>sh ip bgp

BGP routing table entry for, version 7068

Paths: (1 available, best #1, table Default-IP-Routing-Table)

Not advertised to any peer

4773 65204, (aggregated by 65204 from (

Origin IGP, localpref 100, valid, external, atomic-aggregate, best

Extended Community: RT:4773:4801


Re: BGP not advertising a particular subnet

Try routing to a null interface. Be sure you have more specific routes in your IGP.

interface null0

ip route null0

Don't forget to soft reset the BGP advertisement.

clear ip bgp soft out

Re: BGP not advertising a particular subnet


I would advice first do a

sh ip route | i

if there you cannot find anything related to this subnet, then follow the steps from medan post.

@medan, very good explanation, you have your post rated by me.

Best regards,


Re: BGP not advertising a particular subnet

Thanks Calin, your advice is good also in case there is already a route locally.

CreatePlease login to create content