Path: utzoo!utgpu!water!watmath!clyde!bellcore!rutgers!ucsd!nosc!helios.ee.lbl.gov!ace.ee.lbl.gov!leres
From: leres@ace.ee.lbl.gov (Craig Leres)
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  A host sending an ARP request to itself?
Message-ID: <438@helios.ee.lbl.gov>
Date: 10 Jul 88 23:54:16 GMT
References: <8807082155.AA03962@uc.msc.umn.edu>
Sender: usenet@helios.ee.lbl.gov
Reply-To: leres@helios.ee.lbl.gov (Craig Leres)
Organization: Lawrence Berkeley Laboratory, Berkeley
Lines: 12

Stuart Levy writes:
> It's probably trying to tell the world that it itself (its own IP address)
> is at its own Ethernet address... just in case they forgot or otherwise
> got confused.  It could also be checking for impostors on the same net,
> claiming to be the same IP address as its own.

I think the best reason for gratuitously broadcasting an arp reply
for yourself is to force hosts you were talking to (say, before you
shutdown, swapped your ethernet interface, and rebooted) to learn your
new hardware ethernet address.

		Craig