12-18-2001
Perhaps I'm missing something fundemental to DNS name resolution here. If I've only got my own local Nameserver in the resolv.conf and that has no information about
www.yahoo.com (or anything else for that matter), why does it not transcend all the way down to the root nameservers (which it knows about through the root hints file - the addresses are valid I can ping them) and get me a valid answer by issuing iterative queries to Nameservers until it finds an authoritative answer?
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LEARN ABOUT DEBIAN
net::dns::resolver::recurse
Net::DNS::Resolver::Recurse(3pm) User Contributed Perl Documentation Net::DNS::Resolver::Recurse(3pm)
NAME
Net::DNS::Resolver::Recurse - Perform recursive dns lookups
SYNOPSIS
use Net::DNS::Resolver::Recurse;
my $res = Net::DNS::Resolver::Recurse->new;
DESCRIPTION
This module is a sub class of Net::DNS::Resolver. So the methods for Net::DNS::Resolver still work for this module as well. There are just
a couple methods added:
hints
Initialize the hint servers. Recursive queries need a starting name server to work off of. This method takes a list of IP addresses to use
as the starting servers. These name servers should be authoritative for the root (.) zone.
$res->hints(@ips);
If no hints are passed, the default nameserver is asked for the hints. Normally these IPs can be obtained from the following location:
ftp://ftp.internic.net/domain/named.root
recursion_callback
This method is takes a code reference, which is then invoked each time a packet is received during the recursive lookup. For example to
emulate dig's "+trace" function:
$res->recursion_callback(sub {
my $packet = shift;
$_->print for $packet->additional;
printf(";; Received %d bytes from %s
",
$packet->answersize,
$packet->answerfrom
);
});
query_dorecursion
This method is much like the normal query() method except it disables the recurse flag in the packet and explicitly performs the recursion.
$packet = $res->query_dorecursion( "www.netscape.com.", "A");
IPv6 transport
If the appropriate IPv6 libraries are installed the recursive resolver will randomly choose between IPv6 and IPv4 addresses of the
nameservers it encounters during recursion.
If you want to force IPv4 transport use the force_v4() method. Also see the IPv6 transport notes in the Net::DNS::Resolver documentation.
AUTHOR
Rob Brown, bbb@cpan.org
SEE ALSO
Net::DNS::Resolver,
COPYRIGHT
Copyright (c) 2002, Rob Brown. All rights reserved. Portions Copyright (c) 2005, Olaf M Kolkman.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
$Id: Recurse.pm 740 2008-12-17 23:20:53Z olaf $
perl v5.14.2 2009-12-30 Net::DNS::Resolver::Recurse(3pm)