NAME
Net::DNS::Update - Create a DNS update packet
SYNOPSIS
use Net::DNS::Update;
DESCRIPTION
Net::DNS::Update is a subclass of Net::DNS::Packet, to be used for making DNS dynamic updates. Programmers should refer to RFC 2136 for the semantics of dynamic updates.
WARNING: This code is still under development. Please use with caution on production nameservers.
METHODS
new
$packet = Net::DNS::Update->new;
$packet = Net::DNS::Update->new('example.com');
$packet = Net::DNS::Update->new('example.com', 'HS');Returns a Net::DNS::Update object suitable for performing a DNS dynamic update. Specifically, it creates a packet with the header opcode set to UPDATE and the zone record type to SOA (per RFC 2136, Section 2.3).
Programs must use the push method to add RRs to the prerequisite, update, and additional sections before performing the update.
Arguments are the zone name and the class. If the zone is omitted, the default domain will be taken from the resolver configuration. If the class is omitted, it defaults to IN.
Future versions of Net::DNS may provide a simpler interface for making dynamic updates.
safe_push
$update->safe_push(pre => $rr);
$update->safe_push(update => $rr);
$update->safe_push(additional => $rr);Adds unseen RRs to the specified section of the update. This is useful to insure that the udpates do not contain redundant RRs in any of the sections.
EXAMPLES
The first example below shows a complete program; subsequent examples show only the creation of the update packet.
Add a new host
#!/usr/bin/perl -w
use Net::DNS;
use strict;
# Create the update packet.
my $update = Net::DNS::Update->new('example.com');
# Prerequisite is that no A records exist for the name.
$update->push(pre => nxrrset('foo.example.com. A'));
# Add two A records for the name.
$update->push(update => rr_add('foo.example.com. 86400 A 192.168.1.2'));
$update->push(update => rr_add('foo.example.com. 86400 A 172.16.3.4'));
# Send the update to the zone's primary master.
my $res = Net::DNS::Resolver->new;
$res->nameservers('primary-master.example.com');
my $reply = $res->send($update);
# Did it work?
if ($reply) {
if ($reply->header->rcode eq 'NOERROR') {
print "Update succeeded\n";
} else {
print 'Update failed: ', $reply->header->rcode, "\n";
}
} else {
print 'Update failed: ', $res->errorstring, "\n";
}Add an MX record for a name that already exists
my $update = Net::DNS::Update->new('example.com');
$update->push(pre => yxdomain('example.com'));
$update->push(update => rr_add('example.com MX 10 mailhost.example.com'));Add a TXT record for a name that doesn't exist
my $update = Net::DNS::Update->new('example.com');
$update->push(pre => nxdomain('info.example.com'));
$update->push(update => rr_add('info.example.com TXT 'yabba dabba doo''));Delete all A records for a name
my $update = Net::DNS::Update->new('example.com');
$update->push(pre => yxrrset('foo.example.com A'));
$update->push(update => rr_del('foo.example.com A'));Delete all RRs for a name
my $update = Net::DNS::Update->new('example.com');
$update->push(pre => yxdomain('byebye.example.com'));
$update->push(update => rr_del('byebye.example.com'));Perform a signed update
my $key_name = 'tsig-key';
my $key = 'awwLOtRfpGE+rRKF2+DEiw==';
my $update = Net::DNS::Update->new('example.com');
$update->push(update => rr_add('foo.example.com A 10.1.2.3'));
$update->push(update => rr_add('bar.example.com A 10.4.5.6'));
$update->sign_tsig($key_name, $key);Another way to perform a signed update
my $key_name = 'tsig-key';
my $key = 'awwLOtRfpGE+rRKF2+DEiw==';
my $update = Net::DNS::Update->new('example.com');
$update->push(update => rr_add('foo.example.com A 10.1.2.3'));
$update->push(update => rr_add('bar.example.com A 10.4.5.6'));
$update->push(additional => Net::DNS::RR->new("$key_name TSIG $key"));Perform a signed update with a customized TSIG record
my $key_name = 'tsig-key';
my $key = 'awwLOtRfpGE+rRKF2+DEiw==';
my $tsig = Net::DNS::RR->new("$key_name TSIG $key");
$tsig->fudge(60);
my $update = Net::DNS::Update->new('example.com');
$update->push(update => rr_add('foo.example.com A 10.1.2.3'));
$update->push(update => rr_add('bar.example.com A 10.4.5.6'));
$update->push(additional => $tsig);BUGS
This code is still under development. Please use with caution on production nameservers.
COPYRIGHT
Copyright (c) 1997-2002 Michael Fuhr.
Portions Copyright (c) 2002-2003 Chris Reinhardt.
All rights reserved. This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.
SEE ALSO
perl(1), Net::DNS, Net::DNS::Resolver, Net::DNS::Header, Net::DNS::Packet, Net::DNS::Question, Net::DNS::RR, RFC 2136, RFC 2845