gistfile1.pl

#!/usr/bin/perl -w

# Dependence: Net::DNS
# To get correct answers, use TCP.
# I am not going to say more.

use strict;
use Net::DNS;
use Net::DNS::Nameserver;

my $resolver = Net::DNS::Resolver->new(
        nameservers => [qw(8.8.8.8 4.2.2.1 4.2.2.5)],
        usevc       => 1,
        debug       => 1,
);

sub reply_handler {
    my ($qname, $qclass, $qtype) = @_;
    my $packet = $resolver->send($qname, $qtype, $qclass);
      
    return (
        $packet->header->rcode,
        [ $packet->answer     ],
        [ $packet->authority  ],
        [ $packet->additional ],
    );
}

my $ns = Net::DNS::Nameserver->new(
    LocalAddr    => "127.0.0.1",
    LocalPort    => 53,
    ReplyHandler => \&reply_handler,
    Verbose      => 1,
) or die "couldn't create nameserver object\n";

$ns->main_loop;