The Perl FAQ suggests the following:

use Socket      qw( inet_ntoa );
use Net::Domain qw( hostfqdn );

my $my_host = hostfqdn();
my $my_ip   = inet_ntoa scalar gethostbyname $host;
[download]

You should also read up the FAQ on the name of the language.

Updated. I misread it the FAQ the first time around.