#!/usr/bin/perl -w
use strict;
use NetAddr::IP;
use Net::DNS::Resolver;

my $res = new Net::DNS::Resolver;

# For domains in CCTLDs, you need to ask root-servers.net instead
# and follow the delegation chain.

$res->nameservers(NetAddr::IP->new("g.gtld-servers.net")->addr);

for my $dom (map { chomp; $_ } <DATA>)
{
    my $packet = $res->query($dom, 'NS');

    # No answer received...
    unless ($packet)
    {
	warn "No response for $dom\n";
	next;
    }

    # A DNS answer (response) was received but ...
    my @answer = $packet->answer;

    # ... it might not contain real answers ...
    unless (@answer)
    {
	warn "Response packet contains no answer section for $dom\n";
	next;
    }
    
    # ... or it might be what I am looking for.
    for my $s (@answer)
    {
	next unless $s->type eq 'NS';
	print "$dom: ", $s->nsdname, "\n";
    }
}

__END__
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