🚀 go-pugleaf

> >Can you subnet a Class C address, say by using a mask like 255.255.255.128?
> >We have two Novell networks that we are with an Ethernet bridge between them.
> >Right now, it looks like we will need three Class C address for this:
> >one for each ring, and one for the Ethernet bridge. Since the rings are only
> >going to have like 20 or 30 clients on each, it seems extremely wasteful to
> >use 3*255 potential addresses to serve 60 clients.
> Absolutely.  We're masking at the .192 level (0xC0) and for our backbone
> at the .240 (0xF0) level.
>
> However -- we've found out -- the very hard way -- over the last two days
> that CISCO routers don't like varying subnet masking.  What we had was:
>
>
>
>   ----------CISCO-----NOVELL-----ws
>   IPX=13487     IXP=13496   IPX=13411
>   IP=x.x.240.2              IP=x.x.246.2
>   255.255.255.0  255.255.255.240     255.255.255.192
>
> The WS on the left can see the CISCO.  The WS on the right can see the
> CISCO.  From inside Mr. CISCO you can see both.  The WS on the left
> can login to the netware server.  The WS on the left can't ping the WS
> on the right (nor, more important, can the WS on the right talk to the
> MVS host on the left)...
>
> Ouch...
>
> So, be careful out there, test everything!
>
> Seriously, though, it does work.  It's a software limitation of the
> CISCO, which will be fixed RSN (6-8 months)...

Baloney.

Certainly a class C net can be subnetted. You can have variable length subnet
masks - as long as you use a sensible routing protocol like OSPF. RIP does not
carry the necessary information (subnet mask length).

Steinar Haug, system/networks administrator
SINTEF RUNIT, University of Trondheim, NORWAY
Email: Steinar.Haug@runit.sintef.no, Steinar.Haug@delab.sintef.no