#!/usr/local/bin/perl
unless (eval { &AF_INET }) {
    eval { require 'socket.ph'; } || eval { sub AF_INET {2} };
}

foreach (@ARGV) {
    if (/^\d{1,3}\.\d{1,3}\.\d{1,3}.\d{1,3}$/) {
	$name = (gethostbyaddr(pack("C4",split(/\./)),&AF_INET))[0];
	if ($name) {
	    print "$name\n";
	} else {
	    warn "$_: can't get remote hostname\n";
	}
    } else {
	warn "$_: badly formed IP address\n";
    }
}