RE: [nsp] BGP default-originate

From: Martin, Christian (cmartin@gnilink.net)
Date: Thu Jan 04 2001 - 16:57:03 EST


> This worked for me using 12.0(14).
>
> Make sure the static route next hop is in the routing table,
> BGP requires
> a default route exist in the routing table before advertising
> it to BGP
> neighbors.

This is not the case. BGP does not require a default to exist in the table
to inject a default with default-originate.

-Scott
>
> On Thu, 4 Jan 2001 Insik_Park@infonet.com wrote:
>
> > Hello all,
> >
> > I am trying to inject default route 0.0.0.0 to eBGP neighbor using
> > default-originate and route map, but it doesn't seem to
> work. Below is the
> > configuration. Am I missing something? If I use
> default-originate without
> > route-map, then it successfully injects default network to
> eBGP neighbor.

I believe the route-map matching logic, when used with an access-list, is
there to determine what the next-hop is. Your route-map doesn't perform
this matching. You would use it to say something like this:

router bgp 200
 neighbor 200.100.1.2 remote-as 400
 neighbor 200.100.1.2 default-originate route-map default-map
!
route-map default-map permit 10
match ip next-hop 1
!
access-list 1 permit 192.168.1.1

Then, the route-map would fail if there wasn't a default to the next-hop.

Another way to do it would be with an extended access-list as such:

router bgp 200
 neighbor 200.100.1.2 remote-as 400
 neighbor 200.100.1.2 default-originate route-map default-map
!
route-map default-map permit 10
match ip address 101
!
access-list 101 permit ip host 0.0.0.0 host 192.168.1.1

This is sort of a conditional advertisement.

For your purposes, you do not need the route-map, as this command only
injects a default. If you are trying to prevent leakage of other prefixes,
use a distribute/prefix list.

chris

> >
> > !
> > router bgp 200
> > neighbor 200.100.1.2 remote-as 400
> > neighbor 200.100.1.2 default-originate route-map default-map
> > !
> > route-map default-map permit 10
> > match ip address 1
> > !
> > access-list 1 permit 0.0.0.0
> > !
> > ip route 0.0.0.0 0.0.0.0 195.190.1.1
> >
> > ------------------
> > !
> > router bgp 400
> > neighbor 200.100.1.1 remote-as 200
> >
> >
> >
> >
>
>



This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:24 EDT