Path: utzoo!attcan!uunet!cs.utexas.edu!wuarchive!rice!rice!sun-spots-request
From: jhd@maths.bath.ac.uk
Newsgroups: comp.sys.sun
Subject: Re: random subnet mask change
Keywords: Networks
Message-ID: <1990Oct26.221636.18849@rice.edu>
Date: 26 Oct 90 23:10:00 GMT
Sender: sun-spots-request@rice.edu
Organization: Sun-Spots
Lines: 17
Approved: Sun-Spots@rice.edu
Originator: spots@titan.rice.edu
X-Sun-Spots-Digest: Volume 9, Issue 343, message 1
X-Original-Date: Mon, 8 Oct 90 12:31:32 BST
X-Refs:  Original: v9n342

In article <1990Oct8.002204.13482@rice.edu> jet@karazm.math.uh.edu (J. Eric Townsend) writes:
>Sep  6 15:08:45 karazm vmunix: Setting subnet mask to 0xfffff000
>
>The correct mask for us is "0xffff0000".  I checked le0 with ifconfig, and
>sure enough, it had been changed.  So I put it back. :-) Any ideas on what
>causes this and how I can stop it?

What causes it is that some other machine on your network broadcasts an
ICMP address mask reply message, and your ever-trusting Sun just believes
it. The solution is to find out WHO is doing this broadcast. Needless to
say, this is easier said than done. Getting hold of tcpdump and running it
with an appropriate filter (for broadcasts) would do it, but it's a
tedious process. The alternative solution is hunt around your physical
network for some machine that has this incorrect netmask. Good luck!

James Davenport
jhd@maths.bath.ac.uk