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.

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.