Re: Removing Default route propagation

From: Narbik Kocharians (narbikk@gmail.com)
Date: Tue Feb 24 2009 - 19:34:02 ARST

If the default route is injected on let's say R1 and we should NOT see it on
the neighboring router R2, then it all depends on how the default route was
injected.

If the default route was injected by redistributing static, then an IP
prefix-list and a distribute-list command will filter it on R2, *but if we
can NOT use the prefix-lists/distribute-list*, we can use a
"*distance eigrp 90 255*" where an AD of 90 is applied to all internal
routes and an AD of 255 is applied to all external routes. Therefore, the
external routes will NOT be in our routing table.

If the default route was injected by using the "*IP Default-network*"
command, then the "*no default-information allowed in*" can be used on R2,
but remember that the network that is set as the candidate will still be in
the routing table, unless it is filtered as well.

On Tue, Feb 24, 2009 at 1:01 PM, Ronnie Angello <ronnie.angello@gmail.com>wrote:

> I would think that 'no default-information in' should work on the
> router that's redistributing the static because it's redistributing
> external information into the AS. I did lab this up and, as you said,
> it does not work as expected. The default is marked as candidate on
> the neighbor router. I verified that it has the D*EX designation.
> Anyway, why would we want to redistribute a static default route if we
> didn't want our neighbors to receive it anyway? Yes, I know... It's
> the CCIE lab!
>
> Is the requirement written "must not be received" or "must not be
> used/installed in the neighbor routing table?" You could create a
> summary on the neighbor router for 0.0.0.0/0 on a loopback interface
> so that the discard route to null 0 is used instead of the external
> route (because of AD of 5). That would make it so the neighbor would
> not use the route or install it in its routing table, but technically
> it does still receive it and puts it in the EIGRP topology table.
>
> On Tue, Feb 24, 2009 at 12:09 PM, Robin.B <ro.betterley@gmail.com> wrote:
> > Hello GS,
> >
> > My EIGRP has a default route being propagated via redistributed static.
> I
> > understand that this is the nature of EIGRP process.
> >
> > I need to deny this default route from being received by my neighbors. Do
> not
> > use any form of route-map or distribute-list. Can someone explain how
> should I
> > place the "no default information-originate" ? I have tested it but it
> doesn't
> > seems to achieve the result.
> >
> > Thanks in advance.
> >
> >
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> Ronald Angello
> CCIE 17846
> CCDP, CCIP, CCNP
>
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-- 
Narbik Kocharians
CCSI#30832, CCIE# 12410 (R&S, SP, Security)
www.MicronicsTraining.com
www.Net-Workbooks.com
Sr. Technical Instructor

Blogs and organic groups at http://www.ccie.net

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