🚀 go-pugleaf

  >     Date:        27 Aug 92 16:36:57+0200
  >     From:        Peter Merdian <merdian@rus.uni-stuttgart.dbp.de>
  >     Message-ID:  <2299*merdian@rus.uni-stuttgart.dbp.de>
  > 
  >     According to RFC 950 only one subnetmask is allowed for an IP network:
  > 
  > I don't think this is true - RFC950 is not highly clear on
  > the point, but it does seem to suggest that different masks
  > on different interfaces is possible - and it never says that
  > that should only happen if the different interfaces are on
  > different nets.
  > 
  > The problem was never really the spec, but the implementations,
  > which with any luck will be gradually getting fixed.
well, I hear of systems manufactured today (but not by Cisco:-) still
not supporting subnet masks - so fixing can take quite some while.

Regarding the subnet support on Cisco routers:

- I remember old releases that copied the subnet mask specified from the
  "address" config command to all interfaces connected to subnets of the
  same common net - thus enforcing a common mask

- I think recent releases allow to configure different masks;

I think I did not see any documentation telling about
- the old restriction
- removal of the restriction
- explanation what the routers actually are doing now with different masks
  (just straight forward the right thing?)
  
- Ruediger


Ruediger Volk
Universitaet Dortmund, Informatik IRB				DE-NIC
Postfach 500 500
D-W-4600 Dortmund 50
Germany

E-Mail: rv@Informatik.Uni-Dortmund.DE
Phone:  +49 231 755 4760                 Fax:  +49 231 755 2386