Re: lib/50367: libc resolver library does not resolve host names with underscores ("_")

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sun, 25 Oct 2015 14:13:11 +1030
    From:        Brett Lymn <blymn%internode.on.net@localhost>
    Message-ID:  <20151025034311.GA1222%internode.on.net@localhost>

  | That is actually the correct behaviour, underscores are not legal in
  | hostnames.

That's correct, for hostnames being entered into hostnames.txt (a file
that hasn't existed in any meaningful form for 30 years.)

There are no constraints on names that can appear in the DNS (only a
recommendation on what was good to use, in the mid 80's, for compat
with old software), and hence there should be no constraints on what
can be resolved (just adding '_' to a magic list of acceptable chars
is wrong.)

e-mail domain names are a whole other issue of course, similarly names
used with other protocols that might have various limitations, and as are
the set of chars that NetBSD (or any other OS) permits for the
sethostname(2) syscall.

kre