SUMMARY: IP routing

From: Patrick McAndrew (patrick@icbl.heriot-watt.ac.uk)
Date: Sat Jul 04 1992 - 14:31:26 CDT


Summary of replies to my question about IP routing.

I asked essentially if it was possible to mix subnet masks on a class B
network to allow sections of the campus to avoid getting routers.

>From the replies there was
  1 yes it should work but some routes will need to be added manually.
  1 what you have at the moment is wrong (which I knew).
  3 Don't mess with subnetmasks! I.e. stick with one across all networks,
preferably 255.255.255.0

Other interesting points were a summary document from Rutgers about IP and
point to the relevant RFCs. There was also mention of the need to turn
packet forwarding on with ifconfig. This does not seem to be an option
with Suns, although there is something similar on the DecStations.

So what did we do. Well rather to my disappointment we have stopped
playing with subnet masks and did not try the experiment with mixing masks
252 and 255 but, as advised, have gone for netmask 255.255.255.0
for all machines, assigned 137.195.151.xx numbers to machines connected
to the lan (the gateways and Computing Services machines). Further
Departments connecting to the lan will need routers or be part of the 254
machines that can have 151 addresses. This is not ideal but has the huge
advantage that it works!

Thanks to:
 ems@ccrl.nj.nec.com (Ed Strong)
 "Anthony A. Datri" <datri@concave.convex.com>
 geertj@ica.philips.nl (Geert Jan de Groot)
 Neil W Rickert <rickert@cs.niu.edu>
 kjv@tampella.fi (V{{r{nen Kari)

Full copies of replies avialable on request.

Patrick.
---------
Patrick McAndrew
System Manager
Institute for Computer Based Learning
Heriot-Watt University
Edinburgh EH14 4AS



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