Re: BGP issue

From: Patrick Galligan (pgalligan@gmail.com)
Date: Tue Apr 22 2008 - 07:04:08 ART

I've just done this on a couple of switches:

3750 - iBGP - 3560

On both:
router bgp 200
 net 10.0.0.0 mask 255.0.0.0
 neigh blah

ip route 10.0.0.0 255.0.0.0 null0

I see both routes in the BGP table on both switches. I see the same
behaviour at customer sites where I'm originating their public block
from both routers to each ISP, with a static pointing to their
firewall/s, and run iBGP between the customer routers.

Noor, have run done any debugs?

eg. deb ip bgp update

and then

clear ip bgp <neighbour address>

Are you running on Dynamips or real routers? What IOS?

On Tue, Apr 22, 2008 at 5:47 PM, Nikhil Engineer <ccienovice@gmail.com> wrote:
> hi Noor,
>
> As I said before this is due to split horizon.
>
>
> Cheers,
> Nikhil E
>
>
> On 4/22/08, Noor.Yousuf@shell.com <Noor.Yousuf@shell.com> wrote:
> >
>
>
> > Amir,
> >
> > I understand your point, and I know that it is locally originated again
> > and it is in the bgp table but I would only like to know the reason why the
> > same route from R3 is not in the BGP table anymore?
> >
> > Thanks,
> >
> > -----Original Message-----
> > From: Amir.Tahir/Wateen/Lahore [mailto:Amir.Tahir@wateen.com]
> > Sent: dinsdag 22 april 2008 9:28
> > To: Yousuf, Noor S SITI-ITIBTAE; ccielab@groupstudy.com
> > Cc: itsfortarget@gmail.com; smorris@ipexpert.com; sadiqtanko@gmail.com
> > Subject: RE: BGP issue
> >
> >
> > Dear Noor,
> >
> > When you have advertised 200.200.200.0/24 on R3, why you are advertising
> > same network Prefix on R2.
> >
> > If you have eBGP relationship between R1 & R3, you should learn 200
> > prefix from R3 and should be visible on R2 as well. You don't have to
> > re-advertise it.
> >
> > If you have eBGP relation between R2 & R4, it should be propagated to R4
> > through the AS (Defined on R2 & R1)...
> > If Ip route command confuse you, try to run rip between R1 & R2 to have
> > the NLRI reachibility..
> >
> > As far as you query is concern... you have defined the 200 prefix
> > through Network command on R2 and now its locally advertised. You could
> > verify it through Weight (32768) & AS Path (i).
> >
> >
> > r2#SH IP BGP
> > BGP table version is 8, local router ID is 2.2.2.2
> > 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
> > *> 200.200.200.0 0.0.0.0 0 32768 i
> >
> >
> > If still you are not clear, Please feel free to call me at
> > 0322-400-2647(amir)
> >
> >
> > Regards
> > __________________
> > Amir Tahir
> >
> >
> > -----Original Message-----
> > From: Noor.Yousuf@shell.com [mailto:Noor.Yousuf@shell.com]
> > Sent: Tuesday, April 22, 2008 12:12 PM
> > To: Amir.Tahir/Wateen/Lahore; ccielab@groupstudy.com
> > Cc: itsfortarget@gmail.com; smorris@ipexpert.com; sadiqtanko@gmail.com
> > Subject: RE: BGP issue
> >
> > Let me get clear..
> >
> > R3----EBGP---R1----IBGP-----R2----EBGP----R4
> >
> >
> > from R3 I have advertised the network 200.200.200.0 in BGP
> > no sync
> > network 200.200.200.0 mask 255.255.255.0
> > ip route 200.200.200.0 255.255.255.0 Null0
> >
> > I can see the network on R2 bgp table
> > Now I have advertised the same network in R2
> > no sync
> > network 200.200.200.0 mask 255.255.255.0
> > ip route 200.200.200.0 255.255.255.0 Null0
> >
> > As soon as I have advertised the network in R2 BGP, I cannot see the
> > route coming from R1 in the BGP Table, I thought I should see both
> > routes in BGP table but only one in Routing table.
> >
> > r2#SH IP BGP
> > BGP table version is 8, local router ID is 2.2.2.2
> > 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
> > *> 200.200.200.0 0.0.0.0 0 32768 i
> >
> > Can someone explains why?
> >
> > Thanks,
> >
> >
> > Pass the CCIE in six weeks, Guaranteed!
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>
>
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>
> 

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