07-17-2008 10:53 PM - edited 03-03-2019 10:47 PM
Hi all
I have a strange BGP advertising problem and was hoping that someone might be able to give me an answer.
I run BGP on a Catalyst 3750 switch running Enh Image ver 12.2(25r)SE1. On this switch I've configured BGP v4 on it. A router at a remote office is advertising the following subnets: 10.109.3.0/24; 10.109.5.0/24; 10.109.10.0/24; 10.109.100.0/24 and 10.109.200.0/24 to this Cat3750 switch. It's able to receive all 5 subnets just fine but for some reason, it'll only advertise on the first 4 subnets and not the 5th one on 10.109.200.0/24. I checked the switch and this is what it shows:
#sho ip bgp 10.109.3.0
BGP routing table entry for 10.109.3.0/24, version 1627
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Advertised to update-groups:
2
64900 64900
192.168.157.1 from 192.168.157.1 (10.198.78.36)
Origin IGP, localpref 100, weight 100, valid, external, best
Extended Community: RT:17477:78
#sho ip bgp 10.109.200.0
BGP routing table entry for 10.109.200.0/24, version 1496
Paths: (1 available, best #1, table Default-IP-Routing-Table)
Not advertised to any peer
64900 64900
192.168.157.1 from 192.168.157.1 (10.198.78.36)
Origin IGP, localpref 100, weight 100, valid, external, best
Extended Community: RT:17477:78
The statement "Not advertised to any peer" is clearly the reason for it to not advertise the subnet on to other iBGP peers. I've checked out the link http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800945ff.shtml but it doesn't fix my problem.
Attached is a cut down version of my config and also other show ip bgp xxx commands. Thanks in advance fro your help.
Solved! Go to Solution.
07-18-2008 09:01 AM
Vincent,
I would try using an outbound route-map instead of a distribute-list and see if the problem goes away.
Regards,
07-18-2008 12:55 AM
Hi Vincent, There are a few bugs with the 12.2 IOS train that you are using related to BGP. Try clearing the bgp neighborship and see if that fixes the issue.
07-18-2008 08:58 AM
Vincent,
I would try using an outbound route-map instead of a distribute-list and see if the problem goes away.
Regards,
07-18-2008 09:01 AM
Vincent,
I would try using an outbound route-map instead of a distribute-list and see if the problem goes away.
Regards,
07-20-2008 03:36 PM
Thank you very much for your post. Implementing a simple route map together with a BGP soft resync has now fixed the problem. The command I used is 'clear ip bgp 10.95.3.19 soft out' just in case someone else is interested.
07-18-2008 06:37 PM
Yes I will agree. Infact using route-maps instead of distribute lists is a workaround.
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