Once upon a time, there was confusion about broadcast addresses for LANs
and IP. Long since settled, we all use the all-ones host address for
attached network broadcast (e.g. 192.1.1.255). However, during that time of
confusion, some systems (notably Sun) used the all-zero host address for
broadcast (e.g. 192.1.1.0). When you had two different systems with two
different ideas about what the broadcast address was, Evil Broadcast Storms
resulted (though these unhappy events did have the salutory effect of
convincing the LAN/WAN designers of the time that large bridged
("switched") networks were a Really Bad Idea and that Routers were The Way,
The Truth, and The Light. Some of them had to learn this the hard way, of
course).

Now we live in the time of limited IP address space allocations, where
every address counts, and we have to use our address space efficiently. It
seems a waste to reserve both host address 0 and host address max for any
given network number. Since no one is supposed to be using host address
zero for broadcast any more, the question comes - can it now be used for an
actual host without nasty repercussions, provided one is reasonably certain
that one is running relatively modern software on relatively modern hosts
on one's network?

As an extreme example, can three hosts live on network with a two-bit host
mask (e.g. 255.255.255.252)?

And will NetBSD DTRT?

	curious,

	Erik <fair@clock.org>