> > > You should certainly use the loopback address in preference to
> > > 0.0.0.0, which is entirely bogus. If any implementation accepts it,
> > > it's confused itself.
> > Since most TCP/IP implementations do accept 0.0.0.0 as the local host,
> > and this is a very well known feature, there's no problem with using it
> > where it works.
> This is misleading.

A quick check of RFC 1700 (Assigned Numbers) confirms this; address {0, 0}
means "this host" only when used as a *source* address, and should not be
used as a destination address.  I don't know what the history of {127, any}
is for the loopback address, but it's been official since 11/86 (RFC 990;
it was "reserved" in the version before that, RFC 900).

If there's a right way and a wrong way to go about it, it seems to me that
insisting on using the wrong way because it "works" (now, anyway) is, well,
_wrong_.

(The implementation that let it leak out to the nearest router (an old Sun?)
is even more wrong than one which accepts it as a destination address meaning
"this host".)