[c-nsp] running ip default statements w/ ospf.

[Oliver Boehmer (oboehmer)]

virendra rode // <> wrote on Monday, November 12, 2007 5:53 PM:

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> hi,
> 
> Just wondering if anyone can shed any light into my confusion.
> 
> In looking at a c4506 switch which has ospf running with ip
> default-network 0.0.0.0 / ip default-gateway statements. Not sure the
> reason for these statements when there's routing enabled. I also
> understand that these statements will route packets when there's no
> exact match in the routing table. Also the default route announced
> using the ip default-network command is not propagated by ospf.
> 
> Anyway, so being part of maintenance, I reconfigured the switch from
> area 2 to area 0 with its existing configuration and right after that
> I lost its default route even after the LSA was propagated between
> neighbors. 
> 
> So the first thing I did was to clear the routes include ospf database
> and the default route appeared back, then about a minute I lost the
> default route again. So this time I removed the ip default statements
> which didn't make sense to begin with and this time my default route
> was restored/stable.
> 
> So I jumped onto others switches and noticed they were running ospf
> with the ip default statements w/o any problems?

Hmm, looks like a bug to me. You don't need "ip default-network" with
OSPF if you carry 0.0.0.0/0 in OSPF, I'm considering this as a legacy
command which shouldn't be needed in many networks.

"ip default-gateway" is only applicable whith "no ip routing" (or for
some platform's boot loader when booting from the network).

	oli