From: alain faure (alainfaure@xxxxxxxx)
Date: Sun Jan 13 2002 - 13:01:35 GMT-3
Because,there is a distribute list to forbid 182.16.5.0 in canada for example,
because of some security rule 182.16.5.0 can not be on canada.
--- GerbCraig <gerbermc@mindspring.com> a icrit : > Why isn't the 182.16.5.0
route showing up in Canada's routing table. The
> null0 route will only take effect if a more explicit route does not exist.
> In the case the 182.16.5.0 route should be advertised back towards Canada's
> router.
> ----- Original Message -----
> From: "alain faure" <alainfaure@yahoo.fr>
> To: "Ccielab" <ccielab@groupstudy.com>
> Sent: Sunday, January 13, 2002 6:51 AM
> 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
> table
> > 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
> some
> > > little changes).
> > >
> > > when i do manual summarization on the serial interface of canada 1 i got
> the
> > > 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
> NULL0
> > > 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
> > >
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:56:26 GMT-3