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.