🚀 go-pugleaf

landin@cherokee.nsuok.edu (Mark Landin) writes:

>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)...

-----Burton