CIDR on 3Com Netbuilder

Brian Horvitz horvitz at
Fri Jul 31 13:00:58 UTC 1998

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.


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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