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+.. SPDX-License-Identifier: GPL-3.0-or-later
+
+.. _mod-dns64:
+
+DNS64
+=====
+
+The module for :rfc:`6147` DNS64 AAAA-from-A record synthesis, it is used to enable client-server communication between an IPv6-only client and an IPv4-only server. See the well written `introduction`_ in the PowerDNS documentation.
+If no address is passed (i.e. ``nil``), the well-known prefix ``64:ff9b::`` is used.
+
+.. _introduction: https://doc.powerdns.com/md/recursor/dns64
+
+Simple example
+--------------
+
+.. code-block:: lua
+
+	-- Load the module with default settings
+	modules = { 'dns64' }
+	-- Reconfigure later
+	dns64.config({ prefix = '2001:db8::aabb:0:0' })
+
+.. warning:: The module currently won't work well with :func:`policy.STUB`.
+   Also, the IPv6 ``prefix`` passed in configuration is assumed to be ``/96``.
+
+.. tip:: The A record sub-requests will be DNSSEC secured, but the synthetic AAAA records can't be. Make sure the last mile between stub and resolver is secure to avoid spoofing.
+
+
+Advanced options
+----------------
+
+TTL in CNAME generated in the reverse ``ip6.arpa.`` subtree is configurable:
+
+.. code-block:: lua
+
+   dns64.config({ prefix = '2001:db8:77ff::', rev_ttl = 300 })
+
+You can specify a set of IPv6 subnets that are disallowed in answer.
+If they appear, they will be replaced by AAAAs generated from As.
+
+.. code-block:: lua
+
+   dns64.config({
+       prefix = '2001:db8:3::',
+       exclude_subnets = { '2001:db8:888::/48', '::ffff/96' },
+   })
+   -- You could even pass '::/0' to always force using generated AAAAs.
+
+In case you don't want dns64 for all clients,
+you can set ``DNS64_DISABLE`` flag via the :ref:`view module <mod-view>`.
+
+.. code-block:: lua
+
+    modules = { 'dns64', 'view' }
+    -- disable dns64 for all IPv4 source addresses
+    view:addr('0.0.0.0/0', policy.all(policy.FLAGS('DNS64_DISABLE')))
+    -- disable dns64 for all IPv6 source addresses
+    view:addr('::/0', policy.all(policy.FLAGS('DNS64_DISABLE')))
+    -- re-enable dns64 for two IPv6 subnets
+    view:addr('2001:db8:11::/48', policy.all(policy.FLAGS(nil, 'DNS64_DISABLE')))
+    view:addr('2001:db8:93::/48', policy.all(policy.FLAGS(nil, 'DNS64_DISABLE')))
+