use Socket;
my $server = "perlmonks.org";
$iaddr = inet_aton($server);
die "No server '$server'\n" unless $iaddr;
$straddr = inet_ntoa($iaddr);
print $straddr, "\n";

# going the other way...
$iaddr = inet_aton($straddr);
$name  = gethostbyaddr($iaddr, AF_INET);
print $name;