[Mimedefang] Net::DNS referral section for a Domain?

[Kevin A. McGrail]

Trying to do some checks on spam by nameservers but I can't figure out 
how to find the referral nameservers for a domain from the root servers.

For example, this snippet is NOT what I need, I don't think:

     use Net::DNS;
     my $res   = Net::DNS::Resolver->new;
     my $reply = $res->query("pccc.com", "NS");

     if ($reply) {
     foreach $rr (grep { $_->type eq 'NS' } $reply->answer) {
         print $rr->nsdname, "\n";
     }
     }
     else {
     warn "query failed: ", $res->errorstring, "\n";
     }

This snippet gets the SOA records which don't have to agree with whois, 
for example:

ns3.pccc.com
ns.2rad.net
ns.pccc.com
ns2.pccc.com

But perhaps it's because our system will check and the servers are 
authoritative.

What we want is the equivalent of a dig +trace referral record which 
would be:

;; Received 486 bytes from 198.41.0.4#53(a.root-servers.net) in 9 ms

pccc.com.               172800  IN      NS      ns.pccc.com.
pccc.com.               172800  IN      NS      ns2.pccc.com.
pccc.com.               172800  IN      NS      ns3.pccc.com.

Any thoughts on how to do that programmatically with Net::DNS?

Regards,
KAM