BGP Default-Originate

Unanswered Question
Mar 5th, 2009

Hello,

I have an eBGP peer with one of my customers, and we currently only send them a default route, using the default-originate command.

When they reboot their router, the session drops of course, but when it comes back up, the session established, but they do not seem to have the default route from the default-originate command, but if I do a soft clear out on the BGP session on our side, everything works great again.

This is kind of annoying, and I was wondering if anyone has experienced this problem before, and has a solution.

I do not have a snapshot of their routing table when this happens yet, but I am working on getting that.

Oddly, I was unable to reproduce this, so I guess it could be something with their configuration, but I am not sure what to look for on their end, as far as configuration that would cause this.

Thanks for any help.

I have this problem too.
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Edison Ortiz Thu, 03/05/2009 - 16:32

Sounds like a bug, what version of IOS are you running on your routers?

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Edison.

Jasonch518_2 Thu, 03/05/2009 - 20:08

I do have soft reconfiguration inbound, but do not think that is playing a factor.

As far as code, I am running:

(s72033_rp-ADVIPSERVICESK9_WAN-M), Version 12.2(33)SXH4, RELEASE SOFTWARE (fc1)

This is a catalyst 6500, with a sup720 3bxl.

The customer side is running 12.4(21) advanced ip services on a 3700 series router.

Edison Ortiz Thu, 03/05/2009 - 20:15

Do you see the 0.0.0.0 being advertised on the show ip bgp ne x.x.x.x advertise-routes ?

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Edison.

Jasonch518_2 Mon, 03/23/2009 - 11:30

Yes.

As an update, I was able to do some more testing, and after the reload of the router, when the session comes back up, they do in fact learn the default route, and it is in the BGP table, however it is not being used, the default route from their iBGP neighbor is being used, so all outbound traffic is going that way,to their backup provider, and inbound is coming in our connection still.

I did some more in depth looking through their show ip route and show ip bgp output, and noticed that after a reload, the AS_PATH for the default route for our connection is now 2 AS deep, our AS, and then one of our upstream providers AS, who we accept a default from.. which would be why it does not use our patch any more, since it is longer.

But problem still seems to be the same though, what causes that default route to be the one in our routing table, instead of default originate.

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