From: Xiangling (xianglingzj@gmail.com)
Date: Wed Jun 06 2007 - 13:34:26 ART
Try a "sh ip bgp 10.10.x.0" and check what is the shown next-hop ( In this
case it should be the IP address of the AS2 router.). Verify the
reachablity of the next-hop by doing a traceroute. Then repeat the
following steps on the last hop you can reach in the traceroute:
If that is no route for the next-hop IP, maybe you should redistribute that
connected interface to your OSPF in AS2.
If there is route but pointing to the wrong patch, you may need to find out
whether this is because wrong configuration of your IGP.
On 6/6/07, CCIE GOAL <ccie.goal@gmail.com> wrote:
>
> Hi guys,
>
> I ran into a problem with BGP, maybe it's simple to resolve but I got
> stuck
> on it.
> People say that sometimes it is easier to spot the issue from outside the
> picture...
>
> Scenario:
>
> [ BGP AS 1 ] -- (OSPF/not in bgp) -- [ BGP AS 2 ] -- [ BGP AS 3 ]
>
> - AS 1 is peering to AS 2
> - AS 2 is peering to AS 3
>
> - Between AS 1 and AS 2; there is some devices in OSPF domain only (Not
> BGP).
>
> - AS 3 is announcing some prefixes, let's say 10.10.X.0/24...
>
> These prefixes are pingable from AS 2 but not from AS 3 even the BGP table
> from AS 3 has these prefix as valid.
>
> The issue is that the OSPF domain do not know how to reach the prefixes
> 10.10.X.0/24.
>
> I am not allowed to use static routes anywhere...
> I have tried to redistribute BGP 2 into OSPF but no success, it seems that
> eBGP learned prefixes are not redistributed...
>
> Can somebody help me on this?
>
> Follow the configs:
>
>
> ---------------------------------------------------
> AS1#
> router bgp 1
> no synchronization
> neighbor 2.2.2.2 remote-as 2
> no auto-summary
> !
> router ospf 1
> network 10.10.1.1 0.0.0.0 area 1
>
> ---------------------------------------------------
> OSPF#
> router ospf 1
> network 10.10.1.2 0.0.0.0 area 1
> network 10.10.2.2 0.0.0.0 area 0
>
> ---------------------------------------------------
> AS2#
> router bgp 2
> no synchronization
> neighbor 1.1.1.1 remote-as 1
> neighbor 3.3.3.3 remote-as 3
> no auto-summary
> !
> router ospf 1
> network 10.10.2.1 0.0.0.0 area 0
> ---------------------------------------------------
>
> AS3#
> router bgp 3
> no synchronization
> neighbor 2.2.2.2 remote-as 2
> no auto-summary
> ---------------------------------------------------
>
>
> Thanks in advance,
> Luciano
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
-- Thanks & Regards, Xiangling |-------------------------| | | \ I Love You All / \ / \___________/
This archive was generated by hypermail 2.1.4 : Sun Jul 01 2007 - 17:24:47 ART