Re: NetBSD Security Advisory 2011-005: ISC dhclient hostname field shell metacharacter injection

[Erik Fair <fair%netbsd.org@localhost>]

Not all domain names are host names. Most of the restrictions on hostnames do 
indeed date from the days of hosts.txt, but most of those restrictions have 
come forward in Internet E-mail standards.

It is still illegal to have a "_" in a host name. You can stick 'em in any 
domain name that isn't going to be used as a host name ...

And, yeah, IDN is screwing up all kinds of things.

        Erik <fair%netbsd.org@localhost>