From: Peter McCreesh (petermccreesh@gmail.com)
Date: Thu Nov 17 2005 - 20:34:53 GMT-3
There is a potential issue with using the 0.0.0.0 <http://0.0.0.0> wildcard
in the following scenario:
R1(10.1.1.1 <http://10.1.1.1>)RIP--------------RIP(10.1.1.2<http://10.1.1.2>
)R2(10.1.2.2
<http://10.1.2.2>)OSPF-----------------OSPF(10.1.2.3<http://10.1.2.3>)R3-----
----[assume
R3 has another route to R1(10.1.1.1 <http://10.1.1.1>)]
If you use the 0.0.0.0 <http://0.0.0.0> wildcard on R2 and redistribute RIP
into OSPF, by default OSPF will advertise itself as the next hop for the
redistributed routes to R3 (nothing to do with the 0.0.0.0
<http://0.0.0.0>wildcard, just normal) but if you wanted R2 to
advertise R1(
10.1.1.1 <http://10.1.1.1>) as the next hop for the redistributed routes to
R3, it wouldn't because the wildcard is specific to the interface and not
the network.
I hope this is explained somewhat clearly!!!!
HTH......Pete
On 11/17/05, Leigh Harrison <ccileigh@gmail.com> wrote:
>
> Just to throw my hat in the ring:-
>
> I ALWAYS specify the interface with a 0.0.0.0 <http://0.0.0.0> wildcard.
> That way it
> will not do anything unexpected to me.
>
> LH
>
> Danny Cox wrote:
>
> >>Dave, get out that off way of putting OSPF Interfaces, I learn that they
> >>could lead us to many errors...
> >>Be very specific if you need to enable OSPF in certains interfaces..
> >>
> >>
> >
> >
> >
> >> network 172.16.16.100 <http://172.16.16.100> 0.0.0.0 <http://0.0.0.0>area
16
> >>
> >>
> >
> >This is off topic, sorry, but why *not* specify it with a matching
> >wildcard mask to the interface as Dave did? Surely from a CCIE lab
> >point of view it doesn't matter so long as the interface ends up
> >participating in the OSPF ?
> >
> >We've actually talked about this at work a bit - is there a consensus
> >as to which is better other than perhaps you're a bit less likely to
> >make mistakes with a 0.0.0.0 <http://0.0.0.0> wildcard mask?
> >
> >cheers
> >Danny
> >
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