John, did you ever try distributing route for 8.0.0.0 instead of 0.0.0.0
to see whether it was true for all routes or just the clammy "normal",
"default" default route :) ?
-------------------------------------------------
Tks | <mailto:[EMAIL PROTECTED]>
BV | <mailto:[EMAIL PROTECTED]>
Sr. Technical Consultant, SBM, A Gates/Arrow Co.
Vox 770-623-3430 11455 Lakefield Dr.
Fax 770-623-3429 Duluth, GA 30097-1511
=================================================
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
John Neiberger
Sent: Tuesday, March 27, 2001 11:19 PM
To: [EMAIL PROTECTED]
Subject: OSPF overrides "no ip classless"
If you recall our recent thread on this, I was noticing that when ospf
would
advertise a default route to another router, the receiving router would
start to behave classlessly even if 'no ip classless' was in the
configuration. This behavior was not seen with eigrp, rip v1, rip v2,
igrp,
or eigrp; only with ospf. This goes against everything I've read about
the
differences between 'ip classless' and 'no ip classless'.
I initially came to the conclusion that it was a 'feature' of that
particular IOS release. Well, I've done some testing with two different
features sets of 11.2(25) on a 4000, and I just tested it again on a
2500
running 12.0(16). The same thing happened!
Someone out there, puhleez explain to me why OSPF is overriding that
command. Shouldn't we be able to leave 'no ip classless' configured if
we
feel like it? I'm not sure why I'd feel like it, I'm just wondering.
Try this out. Connect two routers back to back, A to B. Run anything
but
OSPF between them at first, and set 'no ip classless' on router B.
Configure A to originate a default route. When you see that the gateway
of
last resort is set on B, try to ping A. That should work just fine.
Now
try to ping some other unknown subnet of whatever address space you're
using. For instance, if your A to B link is 10.1.1.0/24, try to ping
10.50.1.1. You should see five timeouts. If you turn on ip packet
debugging, you'll see that the packets were unroutable.
Now configure 'ip classless' on router B and try the ping again. You
will
receive destination unreachable messages from A instead of the timeouts.
Debugging will report that they were forwarded to A, as expected. Now
configure 'no ip classless' on B again.
Remove that routing protocol and run OSPF. When you see the GOLR set on
router B, try to ping an unknown subnet again. This time it will behave
as
if 'ip classless' were configured. Debugging will show that it WAS
routable, even though 'no ip classless' will still be in the
configuration.
Why is this happening? I don't recall seeing this behavior documented.
Someone please confirm my findings (and my sanity) or at least point out
where my thinking is flawed. <g>
Thanks!
John
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