nanog mailing list archives

Re: CIDR on 3Com Netbuilder


From: Brian Horvitz <horvitz () shore net>
Date: Fri, 31 Jul 1998 09:00:58 -0400 (EDT)

Well, I used to have OSPF running on a couple of NetBuilders, and my
biggest complaint was that they didn't support subnet-zero routes.  I had
a bunch of Portmasters advertising routes that the NBs couldn't
understand.  Other than that, it handled CIDR fine.

  Brian

On Thu, 30 Jul 1998, Martin, Christian wrote:

All,

Anyone know how to configure a 3Com NetBuilder to support classless
routing?  Here is the scenario.  I have a class B that is being split up
into 24s and 26s.  All are being statically routed over the respective
WAN interfaces to the customer prem.  Most default back to our WAN
interfaces (some downstream BGP peers, but not in this scenario).
Customer A has a 3Com Netbuilder, with an LAN IP of x.x.200.1 /24.
Customer B has a Cisco 2501 with a LAN IP of x.x.23.1 /24.  This
customer is configured for classless routing using the 'ip classless'
IOS global command.  All customers can see into this network (cust B),
even within the same x.x classfull class B space.  But no one in the
classfull x.x can see into customer A's network.  Actually, their
traffic gets there, but the return traffic never leaves, because the
NetBuilder is looking at the first 3 bits and ignoring it, thinking that
it is local.

3Com thinks that there needs to be static routes in place.  I think that
this is ridiculous, and that CIDR support is necessary in today's
Internet.  It would entail me having to ask a customer to add over 25
static routes for networks that the default rtr (me) knows about.  Does
anyone know how to do this without having a CIDR-aware routing protocol
like OSPF running?  I have had three 3Com guys on the this ticket for
over a week, with no resolution.  3Com employees can redeem their
company by supplying a working solution...Anyone?

Regards,
-Chris




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