Path: utzoo!dciem!nrcaer!scs!spl1!laidbak!att!ulysses!smb
From: smb@ulysses.homer.nj.att.com (Steven Bellovin)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: a proposed modification to ARP
Message-ID: <10435@ulysses.homer.nj.att.com>
Date: 11 Jul 88 14:33:19 GMT
Article-I.D.: ulysses.10435
References: <4462@medusa.cs.purdue.edu>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 9

A more interesting question is how to force hosts to discard ARP entries
for dead machines.  Currently, most implementations keep the ARP entry
for some time interval after the last transmission to a host, not the
last reception from it.  Thus, if a host goes down because of a broken
Ethernet board, some of its partners will retain the old (and now bogus)
address for hours, if contact attempts are sufficiently frequent.  Some
better solution is needed, perhaps akin to the way 4.3bsd quashes a cached
route when the round-trip time gets too long.  It's hard to see a good way
to do that without violating layering, though.