[NTISP] Routing Clue Required

Jeff Woods ( jwoods@delta.com )
Tue, 24 Nov 1998 13:31:47 -0500

I cannot recall if it was on inet-access or on the PM-3 users group, but a
recent thread on one or the other convinced me to move to OSPF vis-a-vis
RIP. However, I need to be equipped with clue.

Current: One "border router" linking us upstream. It doesn't talk BGP or
OSPF as of this time.

IP addrs: a /22, from CIDR, non-portable.

I currently have the vast majority of two consecutive C's used, either by
FTP servers, web servers, or dialup ports. They are NOT sub-netted -- the
entire internal lan is a /23 netmask, handled over a 3Com SuperStack
switched Ethernet switch. This is a Bad Thing (tm).

All IP numbers used below are obviously fake and invalid. I know that.

I want to move to a subnetted architecture, i.e. each PM-3 with its own,
isolated subnet: for the eth0 interface, with a subnet mask
of I'd want to use subnets of different sizes (i.e. a
OM-25 needs a /27, while a PM-3 needs a /26), hence the need for OSPF...

My question is, since RIP will be turned OFF, how does the internal LAN
route? For example, that "border router" at would no longer be
on the same network as the PM-3, and our web servers, which we'd also
isolate, would be similarly "cut off" from the router. I cannot go into
NT (don't start -- I want to know how to do this with NT, not to be
admonised to use YOUR O/S) and set up an IP address of,
netmask and a default gateway of -- the default
gateway isn't on the same LAN, and without RIP, the routing won't happen,
will it? And NT doesn't do OSPF internally, near as I can tell....

I'll need to do this soon, as I will soon need to "dip into" the remaining
addresses. I'd rather not just go change the netmask on all devices to from -- if I have to reconfigure it, I'd rather
reconfigure it CORRECTLY.

So, how can you subnet your internal LAN, and still allow internal routing
to occur? Clue drastically needed, as you can tell. My guess is that I'll
have to set up the 3Com switch as separate networks (yes, it does that) and
let the SWITCH do some internal routing as well, no?

Thanks in advance for any pointers, messages, URLs, or book references.