Subject: Re: Reimplementing broadcast check for ARP
To: None <tech-net@NetBSD.ORG>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-net
Date: 10/02/1997 10:12:31
> When building the new ARP system, I left commented out the test that
> the reported linklevel address is not the broadcast address).

> Problem was that the new ARP system can't know, per se, what the
> broadcast address IS.

This is also assuming that the broadcast cannot be legitimately used in
an arp reply.  I'm not sure whether I think this is true or not.  BUT:

> However, even multicast addresses should be inappropriate for ARP
> entries:

This is definitely false.  I know of at least one system where it is
crucial that a client accept a multicast Ether address in a ARP reply.
(It's a redundant server system, with two or more machines which decide
among themselves who will answer requests; when one dies, the rest
decide who will take over - the reason it's transparent to clients is
precisely that it works by answering arps for the server IP address
with a multicast Ethernet address, one that all the servers set
themselves to receive.)

					der Mouse

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