Re: BGP and AS loop prevention

For the "Show ip bgp neigh xxxx received-routes" to work, you must
pre-configure the routers using the "Neighbor xxxx Soft-reconfiguration in".
Do you have that configured? If NOT, then just use "route" instead of
"received-route". did you do a "clea ip bgp neigh xx in".
It would help for us to see the config.

On Mon, Oct 19, 2009 at 8:46 PM, Johnny B CCIE <jbccie_at_gmail.com> wrote:

> Nate,
>
> Do you think there is a reason that the AS100 will not accept another
> AS100 sending it prefixes? Think about for a moment. What does a BGP
> Speaker do with prefixes if it thinks they came from somewhere else?
> Now ask yourself can you change this behavior and if you can then how
> will you do it?
>
> On Mon, Oct 19, 2009 at 11:12 PM, Nate Lee <natetlee_at_gmail.com> wrote:
> > I have a scenario labbed up where I have an discontiguous BGP AS split
> by
> > another AS, something like this: (AS100) <> (AS 200) <> (AS 100).
> >
> > I am trying to get the prefixes on the AS 100 routers to show up in each
> > others BGP tables. I have implemented the neighbor x.x.x.x allowas-in
> > command on the AS 100 routers on their neighbor statements facing the AS
> 200
> > routers but it does not seem to work. When I do a SHOW IP BGP NEIGH
> x.x.x.x
> > ADVERTISED-ROUTES on the AS 200 routers, I see that the AS 200 router
> will
> > not send the route that originated in the far side AS 100.
> >
> > Is there some sort of configuration needed on the AS 200 routers to allow
> > them to send a route with an AS PATH that contains the AS they are
> sending
> > into? I was under the impression that they do not perform an outgoing AS
> > PATH check.
> >
> > Thanks!
> >
> > Nate
> >
> >
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