I guess in faovour of metric.

"John Neiberger" <[EMAIL PROTECTED]> ¼¶¼g©ó¶l¥ó
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Okay, I just tried this with RIP advertising the default route and I'm
even
> more confused!  Now, it behaves as I would expect.  With no ip classless,
> pings to unknown 10.x.x.x subnets are unroutable even though there is a
> default route in the routing table.
>
> With no ip classless, why does my router take the default route when it
was
> installed by OSPF but not when it was installed by RIP?  I would expect it
> to never take the default route for 10.x.x.x addresses with no ip
classless.
>
> This really concerns me because I was taking a practice CCIE written exam
a
> few days ago and ran across a question like this and I answered the
question
> assuming normal behavior of no ip classless and got it right.  Now I'm
> thinking there are some more twists to its behavior that i'm not aware of.
>
> John
>
> >  Sure, I'll try that but I don't see why it should matter.  As I
> understand
> >  it, ip classless affects routing table lookups only and it doesn't care
> how
> >  those routes were installed into the table.
> >
> >  Although, given this behavior, my assumption might be wrong.
> >
> >  Thanks,
> >  John
> >
> >  >  John,
> >  >  Interesting.  I think this is due to OSPF, not redistribution
problem.
>
> >  Can you try running RIP instead of OSPF ?
> >  >
> >  >  Cheers,
> >  >  YY
> >  >
> >  >
> >  >
> >  >  -----Original Message-----
> >  >  From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf
Of
> >  >  John Neiberger
> >  >  Sent: Sunday, March 25, 2001 5:28 AM
> >  >  To: [EMAIL PROTECTED]
> >  >  Subject: IP Classless Revisited (this is just odd...)
> >  >
> >  >
> >  >  Ok, just when you thought it was safe to go back in the water.... Or
> >  should
> >  >  I say, just when I thought I understood the behavior of 'ip
classess'
> and
> >  >  'no ip classless'....  Let me summarize my lab setup.
> >  >
> >  >  RouterA-----RouterB------RouterC
> >  >
> >  >  Pretty simple.  AtoB is 10.1.1.0/24, BtoA is 10.1.2.0/24.  OSPF is
> >  running
> >  >  on both links.  'ip classless' is on A and C, but not B initially.
On
> B
> >  I
> >  >  see these routes:
> >  >
> >  >       10.0.0.0/24 is subnetted, 2 subnets
> >  >  C       10.1.2.0 is directly connected, Serial1
> >  >  C       10.1.1.0 is directly connected, Serial0
> >  >
> >  >  That's what I expect to see.  Then I add a default route on B, 'ip
> route
> >  >  0.0.0.0 0.0.0.0 10.1.1.2'.  With no ip classless configured, any
> packets
> >  to
> >  >  unknown subnets of 10.0.0.0/8 should be dropped.  I tested it and
that
> is
> >  >  the case.  With 'ip classless' configured, and unknown packets
> regardless
> >  of
> >  >  major network get routed to 10.1.1.2.
> >  >
> >  >  Now here is what I don't understand.  Let's turn off ip classless on
B
> >  >  again, then go to Router C and add a default route to null0 and
> >  >  default-information originate to the ospf process.  I now see this
in
> >  router
> >  >  B:
> >  >
> >  >       10.0.0.0/24 is subnetted, 2 subnets
> >  >  C       10.1.2.0 is directly connected, Serial1
> >  >  C       10.1.1.0 is directly connected, Serial0
> >  >  O*E2 0.0.0.0/0 [110/1] via 10.1.2.2, 00:06:38, Serial1
> >  >
> >  >  There is indeed a default route.  With no ip classless configured, I
> >  would
> >  >  expect the same behavior as before.  If I were to ping 10.5.5.5 the
> >  packets
> >  >  should be unroutable, but they're not!  They get routed to the
default
> >  route
> >  >  whether or not ip classless is configured.
> >  >
> >  >  Why is a default route learned through a routing protocol treated
> >  >  differently than a manually configured default route?  I went
through
> >  this
> >  >  entire process twice and I just don't understand the behavior.
> >  >
> >  >  What am I missing?  I know it's going to be something obvious, but I
> >  don't
> >  >  see it yet.
> >  >
> >  >  Ok, I just now tried this:  with the ospf external default route
still
> in
> >  >  the routing table, I pinged 10.5.5.5 and it took the default route.
> Then
> >  I
> >  >  manually added a default static route and the destination became
> >  unroutable
> >  >  due to 'no ip classless' being configured.  Removing the static
> default
> >  it
> >  >  becomes routable again.
> >  >
> >  >  Weird.  What's going on?
> >  >
> >  >  Thanks,
> >  >  John
> >  >
> >  >
> >  >
> >  >
> >  >
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> >
> >
> >
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>
>
>
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