Re: BGP and AS loop prevention

Good one Andrew.

On Mon, Oct 19, 2009 at 8:58 PM, Narbik Kocharians <narbikk_at_gmail.com>wrote:

> 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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>>
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>
>
> --
> Narbik Kocharians
> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> www.MicronicsTraining.com <http://www.micronicstraining.com/>
> Sr. Technical Instructor
> YES! We take Cisco Learning Credits!
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>

-- 
Narbik Kocharians
CCSI#30832, CCIE# 12410 (R&S, SP, Security)
www.MicronicsTraining.com
Sr. Technical Instructor
YES! We take Cisco Learning Credits!
Training And Remote Racks available
Blogs and organic groups at http://www.ccie.net