SUMMARY: A BETTER SUMMARY: different netmasks w/ two interfaces

From: Mark Natoli (
Date: Fri Oct 01 1999 - 13:26:49 CDT

This is a second summary to this problem.

  I have an Ultra-2 with a FDDI interface and Fast Ethernet interface.
This machine is attached to two separate networks but no routing is done.
All is fine when both cards exist using the same netmask. But when I want
to change the hme0 netmask from to without
changing the mask of the nf0 interface I find this impossible using only
the /etc/inet/netmasks.


where the hme0 is
and the nf0 is

  I have also tried including in the netmasks
file as well as most logical combinations/orders that I could think.

Many thanks to Martin Oksnevad and Eric at Sun.
With out Martin's insistence that it was possible I would have given up.

>From a document sent Eric at Sun:
"The 2.6 kernel has changed to support VLSM. It is now possible to combine
the RFC-950 and RFC-1519 form of subnet masks in the netmasks file.
The network address should be the "SUBNETTED" address NOT the standard
network number based on the hosts ip address. (see man page for netmasks)"

  I see what my problem is, in my original question I did not include the
correct details because the two masks in this scpecfic case are really and The second one is not

  So this works easily

  But this doesn't (which is what I want)

  In order to fix this you need to do this:




Mark Natoli
Systems and Network Administrator
Northeast Parallel Architectures Center, Syracuse University

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