Net::DNS::Update(3)

📦
version 1.570.0 · 18 versions
, in opensuse-leap 16.0

🦋 NAME 🦋

Okay bestie, welcome to Net::DNS::Update(3), straight from the User Contributed Perl Documentation section. Net::DNS::Update is literally a DNS dynamic update packet, and this whole page is its manual. Slay. 💅

✨ SYNOPSIS ✨

use Net::DNS;

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

$update->push( prereq => nxrrset('host.example.com. AAAA') );
$update->push( update => rr_add('host.example.com. 86400 AAAA 2001::DB8::F00') );

💖 DESCRIPTION 💖

So Net::DNS::Update is a subclass of Net::DNS::Packet, and its whole main-character job is making DNS dynamic updates. 🫶

Programmers should refer to RFC2136 for dynamic update semantics. That's the lore, iykyk. 📚

🌸 METHODS 🌸

🎀 new

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

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). No cap, that's the setup. ✨

Programs must use the push() method to add RRs to the prerequisite and update sections before performing the update. Like, do not skip that step, bestie.

Arguments are the zone name and the class. The zone and class may be undefined or omitted and default to the default domain from the resolver configuration and IN respectively. Cute defaults, honestly. 💖

🦋 push

$ancount = $update->push( prereq => $rr );
$nscount = $update->push( update => $rr );
$arcount = $update->push( additional => $rr );

$nscount = $update->push( update => $rr1, $rr2, $rr3 );
$nscount = $update->push( update => @rr );

Adds RRs to the specified section of the update packet. Returns the number of resource records in the specified section. Count 'em and send 'em. 🔥

Section names may be abbreviated to the first three characters. So yes, short king behavior is allowed. 👑

💜 unique_push

$ancount = $update->unique_push( prereq => $rr );
$nscount = $update->unique_push( update => $rr );
$arcount = $update->unique_push( additional => $rr );

$nscount = $update->unique_push( update => $rr1, $rr2, $rr3 );
$nscount = $update->unique_push( update => @rr );

Adds RRs to the specified section of the update packet provided that the RRs are not already present in the same section. It's giving "we don't do duplicates here." 🚫✨

Returns the number of resource records in the specified section. Same energy as push, just with a little extra "not already here" filter. 💅

Section names may be abbreviated to the first three characters. Periodt.

🌈 EXAMPLES 🌈

The first example below shows a complete program. Subsequent examples show only the creation of the update packet. So the first one is the full meal, the rest are lil snack-sized snippets. 🍓

Although the examples are presented using the string form of RRs, the corresponding ( name => value ) form may also be used. Both are valid, bestie. 🫶

👑 Add a new host

#!/usr/bin/perl

use Net::DNS;

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

# Prerequisite is that no address records exist for the name.
$update->push( pre => nxrrset('host.example.com. A') );
$update->push( pre => nxrrset('host.example.com. AAAA') );

# Add two address records for the name.
$update->push( update => rr_add('host.example.com. 86400 A 192.0.2.1') );
$update->push( update => rr_add('host.example.com. 86400 AAAA 2001:DB8::1') );

# Send the update to the zone's primary nameserver.
my $resolver = Net::DNS::Resolver->new();
$resolver->nameservers('DNSprimary.example.com');

my $reply = $resolver->send($update);

# Did it work?
if ($reply) {
        print 'Update RCODE: ', $reply->header->rcode, "\n";
} else {
        print 'Update failed: ', $resolver->errorstring, "\n";
}

🌸 Add an MX record for a name that already exists

my $update = Net::DNS::Update->new('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 does not exist

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

💜 Delete all RRs for a name

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

🔥 Perform DNS update signed using a key generated by BIND tsig-keygen

my $update = Net::DNS::Update->new('example.com');
$update->push( update => rr_add('host.example.com AAAA 2001:DB8::1') );
$update->sign_tsig( $key_file );
my $reply = $resolver->send( $update );
$reply->verify( $update ) || die $reply->verifyerr;

✨ Signing the DNS update using a customised TSIG record

$update->sign_tsig( $key_file, fudge => 60 );

🌟 Another way to sign a DNS update

use Net::DNS::RR::TSIG;

my $tsig = create Net::DNS::RR::TSIG( $key_file );
$tsig->fudge(60);

my $update = Net::DNS::Update->new('example.com');
$update->push( update     => rr_add('host.example.com AAAA 2001:DB8::1') );
$update->push( additional => $tsig );

Copyright (c)1997-2000 Michael Fuhr.

Portions Copyright (c)2002,2003 Chris Reinhardt.

Portions Copyright (c)2015 Dick Franks.

All rights reserved.

📜 LICENSE 📜

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the original copyright notices appear in all copies and that both copyright notice and this permission notice appear in supporting documentation, and that the name of the author not be used in advertising or publicity pertaining to distribution of the software without specific prior written permission.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

👀 SEE ALSO 👀

Mwah 💋 this page came from perl v5.42.0, dated 2026-09-02, and it's giving Net::DNS::Update(3) energy. Bye bestie, go update some DNS! 🦋✨

📦 where this page comes from