The normal way to find your own hostname is to call the `hostname` program. While sometimes expedient, this has some problems, such as not knowing whether you've got the canonical name or not. It's one of those tradeoffs of convenience versus portability.
The Sys::Hostname module (part of the standard perl distribution) will give you the hostname after which you can find out the IP address (assuming you have working DNS) with a gethostbyname() call.
use Socket;
use Sys::Hostname;
my $host = hostname();
my $addr = inet_ntoa(scalar gethostbyname($host || 'localhost'));Probably the simplest way to learn your DNS domain name is to grok
it out of /etc/resolv.conf, at least under Unix. Of course, this
assumes several things about your resolv.conf configuration, including
that it exists.
(We still need a good DNS domain name-learning method for non-Unix systems.)