.. Copyright (C) Internet Systems Consortium, Inc. ("ISC")
..
.. SPDX-License-Identifier: MPL-2.0
..
.. This Source Code Form is subject to the terms of the Mozilla Public
.. License, v. 2.0.  If a copy of the MPL was not distributed with this
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.. See the COPYRIGHT file distributed with this work for additional
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.. highlight: console

.. iscman:: dnssec-dsfromkey
.. program:: dnssec-dsfromkey
.. _man_dnssec-dsfromkey:

dnssec-dsfromkey - DNSSEC DS RR generation tool
-----------------------------------------------

Synopsis
~~~~~~~~

:program:`dnssec-dsfromkey` [ **-1** | **-2** | **-a** alg ] [ **-C** ] [**-T** TTL] [**-v** level] [**-K** directory] {keyfile}

:program:`dnssec-dsfromkey` [ **-1** | **-2** | **-a** alg ] [ **-C** ] [**-T** TTL] [**-v** level] [**-c** class] [**-A**] {**-f** file} [dnsname]

:program:`dnssec-dsfromkey` [ **-1** | **-2** | **-a** alg ] [ **-C** ] [**-T** TTL] [**-v** level] [**-c** class] [**-K** directory] {**-s**} {dnsname}

:program:`dnssec-dsfromkey` [ **-h** | **-V** ]

Description
~~~~~~~~~~~

The :program:`dnssec-dsfromkey` command outputs DS (Delegation Signer) resource records
(RRs), or CDS (Child DS) RRs with the :option:`-C` option.

By default, only KSKs are converted (keys with flags = 257).  The
:option:`-A` option includes ZSKs (flags = 256).  Revoked keys are never
included.

The input keys can be specified in a number of ways:

By default, :program:`dnssec-dsfromkey` reads a key file named in the format
``Knnnn.+aaa+iiiii.key``, as generated by :iscman:`dnssec-keygen`.

With the :option:`-f file <-f>` option, :program:`dnssec-dsfromkey` reads keys from a zone
file or partial zone file (which can contain just the DNSKEY records).

With the :option:`-s` option, :program:`dnssec-dsfromkey` reads a ``keyset-`` file,
as generated by :iscman:`dnssec-keygen` :option:`-C`.

Options
~~~~~~~

.. option:: -1

   This option is an abbreviation for :option:`-a SHA1 <-a>`.

.. option:: -2

   This option is an abbreviation for :option:`-a SHA-256 <-a>`.

.. option:: -a algorithm

   This option specifies a digest algorithm to use when converting DNSKEY records to
   DS records. This option can be repeated, so that multiple DS records
   are created for each DNSKEY record.

   The algorithm must be one of SHA-1, SHA-256, or SHA-384. These values
   are case-insensitive, and the hyphen may be omitted. If no algorithm
   is specified, the default is SHA-256.

.. option:: -A

   This option indicates that ZSKs are to be included when generating DS records. Without this option, only
   keys which have the KSK flag set are converted to DS records and
   printed. This option is only useful in :option:`-f` zone file mode.

.. option:: -c class

   This option specifies the DNS class; the default is IN. This option is only useful in :option:`-s` keyset
   or :option:`-f` zone file mode.

.. option:: -C

   This option generates CDS records rather than DS records.

.. option:: -f file

   This option sets zone file mode, in which the final dnsname argument of :program:`dnssec-dsfromkey` is the
   DNS domain name of a zone whose master file can be read from
   ``file``. If the zone name is the same as ``file``, then it may be
   omitted.

   If ``file`` is ``-``, then the zone data is read from the standard
   input. This makes it possible to use the output of the :iscman:`dig`
   command as input, as in:

   ``dig dnskey example.com | dnssec-dsfromkey -f - example.com``

.. option:: -h

   This option prints usage information.

.. option:: -K directory

   This option tells BIND 9 to look for key files or ``keyset-`` files in ``directory``.

.. option:: -s

   This option enables keyset mode, in which the final dnsname argument from :program:`dnssec-dsfromkey` is the DNS
   domain name used to locate a ``keyset-`` file.

.. option:: -T TTL

   This option specifies the TTL of the DS records. By default the TTL is omitted.

.. option:: -v level

   This option sets the debugging level.

.. option:: -V

   This option prints version information.

Example
~~~~~~~

To build the SHA-256 DS RR from the ``Kexample.com.+003+26160`` keyfile,
issue the following command:

``dnssec-dsfromkey -2 Kexample.com.+003+26160``

The command returns something similar to:

``example.com. IN DS 26160 5 2 3A1EADA7A74B8D0BA86726B0C227AA85AB8BBD2B2004F41A868A54F0C5EA0B94``

Files
~~~~~

The keyfile can be designated by the key identification
``Knnnn.+aaa+iiiii`` or the full file name ``Knnnn.+aaa+iiiii.key``, as
generated by :iscman:`dnssec-keygen`.

The keyset file name is built from the ``directory``, the string
``keyset-``, and the ``dnsname``.

Caveat
~~~~~~

A keyfile error may return "file not found," even if the file exists.

See Also
~~~~~~~~

:iscman:`dnssec-keygen(8) <dnssec-keygen>`, :iscman:`dnssec-signzone(8) <dnssec-signzone>`, BIND 9 Administrator Reference Manual,
:rfc:`3658` (DS RRs), :rfc:`4509` (SHA-256 for DS RRs),
:rfc:`6605` (SHA-384 for DS RRs), :rfc:`7344` (CDS and CDNSKEY RRs).
