From: Alan (groupstudy@xxxxxxxx)
Date: Mon Jan 14 2002 - 02:04:57 GMT-3
why not use a static route to override the default null0 route?
I do not think this problem can be solved easily, anyway.
----- Original Message -----
From: "alain faure" <alainfaure@yahoo.fr>
To: "Ccielab" <ccielab@groupstudy.com>
Sent: Sunday, January 13, 2002 7:51 PM
Subject: Re: AW: avoid null0 with eigrp manual summarization
> Hello,
>
> Yes you are right, but is there another solution ?
>
> Because my problem is ...yes, i know it is a bad design, but real case
> situation :-)
>
> The summary route to null0 may black hole all the packets going out of canada
1
> to a network outside the eigrp AS but not known in the canada 1's routing
> table(For example 182.16.5.0 / 24) and if there is a default route in canada
1.
>
> > canada 1 (s0)--------------30.0.0.0----------------- mexico 1
> > 182.16.3.0 / 24
> > 182.16.4.0 / 24
>
> canada 1's routing table mexico 1's routing tabl
e
> 0.0.0.0 s0 mexico 1 182.16.5.0/24 ethernet 0
> 182.16.0.0 / 16 null0 182.16.0.0/16 canada 1
> 182.16.3.0 / 24 tok 0
> 182.16.4.0 / 24 tok 1
>
> ---(dest:182.16.5.1)----------------------------------->
>
> The packet comming into canada 1 will be black hole by the null0 route.
> If no null0 route, it is ok, it will be forward to mexico 1
>
> Best regards
>
> --- Markus Haas <mh@nmc-m.dtag.de> a icrit : > Normaly the NULL0 route is to
> prevent routing loop (see Dolye V.1 P. 380/381)
> >
> > I think that you cannot avoid the NULL0 route, because it is an default
> > behavior.
> >
> >
> > HTH,
> > Markus
> >
> > -----Urspr|ngliche Nachricht-----
> > Von: nobody@groupstudy.com [mailto:nobody@groupstudy.com]Im Auftrag von
> > alain faure
> > Gesendet: Samstag, 12. Januar 2002 18:47
> > An: ccielab@groupstudy.com
> > Betreff: avoid null0 with eigrp manual summarization
> >
> >
> > Hello,
> >
> > i just bought the ccie pratical studies and try a example page 706 (with so
me
> > little changes).
> >
> > when i do manual summarization on the serial interface of canada 1 i got th
e
> > summary with NULL0 on canada 1 and the summary on mexico witch is correct.
> >
> > canada 1 (s0)--------------30.0.0.0----------------- mexico 1
> > 182.16.3.0 / 24
> > 182.16.4.0 / 24
> >
> > int s0
> > ip add 30.0.0.1 255.0.0.0
> > ip summ eigrp 12 182.16.0.0 255.255.0.0
> >
> > router eigrp 12
> > net 182.16.0.0
> > net 30.0.0.0
> > no auto
> >
> > On page 705 they say auto-summary is bad because it generate a route to NUL
L0
> > so
> > How to avoid route to NULL0 on canada 1 with manual summary ?
> >
> > Thank you very much
> >
> > note : For canada 1 i use : IOS (tm) 2500 Software (C2500-JK8OS-L), Version
> > 12.2(1b)
> >
> > best regards
> >
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