Class: Net::DNS::Update

Inherits:

Packet

• Object
• Packet
• Net::DNS::Update

Defined in:

lib/Net/DNS/Update.rb

Overview

NAME

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

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.

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

require ‘Net/DNS’

# Create the update packet. update = Net::DNS::Update.new_from_values(‘example.com’)

# Prerequisite is that no A records exist for the name. update.push(‘pre’, Net::DNS.nxrrset(‘foo.example.com. A’))

# Add two A records for the name. update.push(‘update’, Net::DNS.rr_add(‘foo.example.com. 86400 A 192.168.1.2’)) update.push(‘update’, Net::DNS.rr_add(‘foo.example.com. 86400 A 172.16.3.4’))

# Send the update to the zone’s primary master. res = Net::DNS::Resolver.new res.nameservers=(‘primary-master.example.com’)

reply = res.send(update)

# Did it work? if (reply)

if (reply.header.rcode == 'NOERROR')
    print "Update succeeded\n"
else
    print 'Update failed: ', reply.header.rcode, "\n"
end

else

print 'Update failed: ', res.errorstring, "\n"

end

Add an MX record for a name that already exists

update = Net::DNS::Update.new_from_values('example.com')
update.push("pre", yxdomain('example.com'))
update.push("update", Net::DNS.rr_add('example.com MX 10 mailhost.example.com'))

Add a TXT record for a name that doesn’t exist

update = Net::DNS::Update.new_from_values('example.com')
update.push("pre", nxdomain('info.example.com'))
update.push("update", Net::DNS.rr_add('info.example.com TXT "yabba dabba doo"'))

Delete all A records for a name

update = Net::DNS::Update.new_from_values('example.com')
update.push("pre", yxrrset('foo.example.com A'))
update.push("update", Net::DNS.rr_del('foo.example.com A'))

Delete all RRs for a name

update = Net::DNS::Update.new_from_values('example.com')
update.push("pre", yxdomain('byebye.example.com'))
$update->push("update", Net::DNS.rr_del('byebye.example.com'))

Perform a signed update

key_name = 'tsig-key'
key      = 'awwLOtRfpGE+rRKF2+DEiw=='

update = Net::DNS::Update.new_from_values('example.com')
update.push('update', Net::DNS.rr_add('foo.example.com A 10.1.2.3'))
update.push('update', Net::DNS.rr_add('bar.example.com A 10.4.5.6'))
update.sign_tsig(key_name, key)

Another way to perform a signed update

key_name = 'tsig-key'
key      = 'awwLOtRfpGE+rRKF2+DEiw=='

update = Net::DNS::Update.new_from_values('example.com')
update.push('update',  Net::DNS.rr_add('foo.example.com A 10.1.2.3'))
update.push('update',  Net::DNS.rr_add('bar.example.com A 10.4.5.6'))
update.push('additional', Net::DNS::RR.create("#{key_name} TSIG #{key}"))

Perform a signed update with a customized TSIG record

key_name = 'tsig-key'
key      = 'awwLOtRfpGE+rRKF2+DEiw=='

tsig = Net::DNS::RR.create("#{key_name} TSIG #{key}")
tsig.fudge=(60)

update = Net::DNS::Update.new_from_values('example.com')
update.push('update', Net::DNS.rr_add('foo.example.com A 10.1.2.3'))
update.push('update', Net::DNS.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 © 1997-2002 Michael Fuhr.

Portions Copyright © 2002-2004 Chris Reinhardt.

Ruby version Copyright © 2006 AlexD (Nominet UK)

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

Net::DNS, Net::DNS::Resolver, Net::DNS::Header, Net::DNS::Packet, Net::DNS::Question, Net::DNS::RR, RFC 2136, RFC 2845

Instance Attribute Summary

Attributes inherited from Packet

#additional, #answer, #answerfrom, #answersize, #authority, #compnames, #header, #question

Class Method Summary

• .new_from_values(zone = nil, klass = nil) ⇒ Object

  Returns a Net::DNS::Update object suitable for performing a DNS dynamic update.

Methods inherited from Packet

#data, #dn_comp, dn_expand, dn_expand_PP, #each_address, #each_cname, #each_mx, #each_nameserver, #each_ptr, #initialize, #inspect, new_from_binary, parse_question, parse_rr, #pop, #push, sign_sig0, #sign_tsig, #unique_push

Constructor Details

This class inherits a constructor from Net::DNS::Packet

Class Method Details

.new_from_values(zone = nil, klass = nil) ⇒ Object

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.

packet = Net::DNS::Update.new_from_values
packet = Net::DNS::Update.new('example.com')
packet = Net::DNS::Update.new('example.com', 'HS')

# File 'lib/Net/DNS/Update.rb', line 169

def Update.new_from_values(zone=nil, klass=nil)
  
  if (zone==nil)
    res = Net::DNS::Resolver.new
    zone = (res.searchlist)[0]
    return unless zone
  end
  
  type  = 'SOA'
  klass  ||= 'IN'
  
  packet = Packet.new_from_values(zone, type, klass) || return
  
  packet.header.opcode=('UPDATE')
  packet.header.rd=(0)
  
  return packet
end