NLnet Labs > Net-DNS > Net::DNS::Update

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Module Version: 1145   Source   Latest Release: Net-DNS-0.74_3

NAME ^

Net::DNS::Update - Create a DNS update packet

SYNOPSIS ^

    use Net::DNS;

    $update = new Net::DNS::Update( 'example.com', 'IN' );

    $update->push( prereq => nxrrset('foo.example.com. A') );
    $update->push( update => rr_add('foo.example.com. 86400 A 192.168.1.2') );

DESCRIPTION ^

Net::DNS::Update is a subclass of Net::DNS::Packet, to be used for making DNS dynamic updates.

Programmers should refer to RFC2136 for dynamic update semantics.

WARNING: This code is still under development. Please use with caution on production nameservers.

METHODS ^

new

    $update = new Net::DNS::Update;
    $update = new Net::DNS::Update( 'example.com' );
    $update = new Net::DNS::Update( '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.

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

    use Net::DNS;

    # Create the update packet.
    my $update = new Net::DNS::Update('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 $resolver = new Net::DNS::Resolver;
    $resolver->nameservers('primary-master.example.com');

    my $reply = $resolver->send($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: ', $resolver->errorstring, "\n";
    }

Add an MX record for a name that already exists

    my $update = new Net::DNS::Update('example.com');
    $update->push( prereq => 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 = new Net::DNS::Update('example.com');
    $update->push( prereq => 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 = new Net::DNS::Update('example.com');
    $update->push( prereq => yxrrset('foo.example.com A') );
    $update->push( update => rr_del('foo.example.com A') );

Delete all RRs for a name

    my $update = new Net::DNS::Update('example.com');
    $update->push( prereq => yxdomain('byebye.example.com') );
    $update->push( update => rr_del('byebye.example.com') );

Perform a DNS update signed using a BIND key file

    my $update = new Net::DNS::Update('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') );
    $update->sign_tsig( "$dir/Khmac-sha512.example.com.+165+01018.private" );

The corresponding public key file may also be used:

    $update->sign_tsig( "$dir/Khmac-sha512.example.com.+165+01018.key" );

Another way to perform a signed update

    my $key_name = 'tsig-key';
    my $key      = 'awwLOtRfpGE+rRKF2+DEiw==';

    my $update = new Net::DNS::Update('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 );

Perform a signed update with a customized TSIG record

    my $key_name = 'tsig-key';
    my $key      = 'awwLOtRfpGE+rRKF2+DEiw==';

    my $tsig = new Net::DNS::RR("$key_name TSIG $key");
    $tsig->fudge(60);

    my $update = new Net::DNS::Update('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) 2002-2004 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, Net::DNS, Net::DNS::Packet, Net::DNS::Header, Net::DNS::RR, Net::DNS::Resolver, RFC 2136, RFC 2845

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