######
use Socket;

open (HOST, ">>hosts.txt") || die "can't open hosts\n";

for ($i = 0; $i< 256; $i++) {
	for ($j = 0; $j< 256; $j++) {
		for ($k = 0; $k< 256; $k++) {
			for ($l = 0; $l< 256; $l++) {
				$iaddr = inet_aton("$i.$j.$k.$l"); # or whatever address
				$name  = gethostbyaddr($iaddr, AF_INET);
				chomp $name;
				print "$i.$j.$k.$l\t$name\n";
				print HOST "$i.$j.$k.$l\t$name\n";
			}
		}
	}
}

close HOST;