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Merge branch '3320-rewrite-arm-dnssec-chapter' into 'main'

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Rewrite DNSSEC ARM Chapter

Closes #3320

See merge request isc-projects/bind9!6296
This commit is contained in:
Michał Kępień
2022-06-22 11:44:11 +00:00
parent f82923a395 146c125988
commit 58102aff42
7 changed files with 496 additions and 477 deletions
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@@ -9,8 +9,6 @@
.. See the COPYRIGHT file distributed with this work for additional .. See the COPYRIGHT file distributed with this work for additional
.. information regarding copyright ownership. .. information regarding copyright ownership.
.. include:: advanced.inc.rst .. include:: dnssec.inc.rst
.. include:: dlz.inc.rst .. include:: managed-keys.inc.rst
.. include:: dyndb.inc.rst .. include:: pkcs11.inc.rst
.. include:: catz.inc.rst
.. include:: rpz.inc.rst

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@@ -9,7 +9,8 @@
.. See the COPYRIGHT file distributed with this work for additional .. See the COPYRIGHT file distributed with this work for additional
.. information regarding copyright ownership. .. information regarding copyright ownership.
.. include:: security.inc.rst .. include:: advanced.inc.rst
.. include:: tsig.inc.rst .. include:: dlz.inc.rst
.. include:: tkey.inc.rst .. include:: dyndb.inc.rst
.. include:: sig0.inc.rst .. include:: catz.inc.rst
.. include:: rpz.inc.rst

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@@ -9,6 +9,7 @@
.. See the COPYRIGHT file distributed with this work for additional .. See the COPYRIGHT file distributed with this work for additional
.. information regarding copyright ownership. .. information regarding copyright ownership.
.. include:: dnssec.inc.rst .. include:: security.inc.rst
.. include:: managed-keys.inc.rst .. include:: tsig.inc.rst
.. include:: pkcs11.inc.rst .. include:: tkey.inc.rst
.. include:: sig0.inc.rst

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@@ -13,261 +13,254 @@
DNSSEC DNSSEC
------ ------
DNS Security Extensions (DNSSEC) provide reliable protection from
`cache poisoning`_ attacks. At the same time these extensions also provide other benefits:
they limit the impact of `random subdomain attacks`_ on resolver caches and authoritative
servers, and provide the foundation for modern applications like `authenticated
and private e-mail transfer`_.
Cryptographic authentication of DNS information is possible through the To achieve this goal, DNSSEC adds `digital signatures`_ to DNS records in
DNS Security ("DNSSEC-bis") extensions, defined in :rfc:`4033`, :rfc:`4034`, authoritative DNS zones, and DNS resolvers verify the validity of the signatures on the
and :rfc:`4035`. This section describes the creation and use of DNSSEC received records. If the signatures match the received data, the resolver can
signed zones. be sure that the data was not modified in transit.
In order to set up a DNSSEC secure zone, there are a series of steps .. note::
which must be followed. BIND 9 ships with several tools that are used in DNSSEC and transport-level encryption are complementary!
this process, which are explained in more detail below. In all cases, Unlike typical transport-level encryption like DNS-over-TLS, DNS-over-HTTPS,
the ``-h`` option prints a full list of parameters. Note that the DNSSEC or VPN, DNSSEC makes DNS records verifiable at all points of the DNS
tools require the keyset files to be in the working directory or the resolution chain.
directory specified by the ``-d`` option.
There must also be communication with the administrators of the parent This section focuses on ways to deploy DNSSEC using BIND. For a more in-depth
and/or child zone to transmit keys. A zone's security status must be discussion of DNSSEC principles (e.g. :ref:`how_does_dnssec_change_dns_lookup`)
indicated by the parent zone for a DNSSEC-capable resolver to trust its please see :doc:`dnssec-guide`.
data. This is done through the presence or absence of a ``DS`` record at
the delegation point.
For other servers to trust data in this zone, they must be .. _`cache poisoning`: https://en.wikipedia.org/wiki/DNS_cache_poisoning
statically configured with either this zone's zone key or the zone key of .. _`random subdomain attacks`: https://www.isc.org/blogs/nsec-caching-should-limit-excessive-queries-to-dns-root/
another zone above this one in the DNS tree. .. _`digital signatures`: https://en.wikipedia.org/wiki/Digital_signature
.. _`authenticated and private e-mail transfer`: https://github.com/internetstandards/toolbox-wiki/blob/main/DANE-for-SMTP-how-to.md
.. _generating_dnssec_keys:
DNSSEC Keys
~~~~~~~~~~~
Generating Keys
^^^^^^^^^^^^^^^
The :iscman:`dnssec-keygen` program is used to generate keys.
A secure zone must contain one or more zone keys. The zone keys
sign all other records in the zone, as well as the zone keys of any
secure delegated zones. Zone keys must have the same name as the zone, have a
name type of ``ZONE``, and be usable for authentication. It is
recommended that zone keys use a cryptographic algorithm designated as
"mandatory to implement" by the IETF. Currently there are two algorithms,
RSASHA256 and ECDSAP256SHA256; ECDSAP256SHA256 is recommended for
current and future deployments.
The following command generates an ECDSAP256SHA256 key for the
``child.example`` zone:
``dnssec-keygen -a ECDSAP256SHA256 -n ZONE child.example.``
Two output files are produced: ``Kchild.example.+013+12345.key`` and
``Kchild.example.+013+12345.private`` (where 12345 is an example of a
key tag). The key filenames contain the key name (``child.example.``),
the algorithm (5 is RSASHA1, 8 is RSASHA256, 13 is ECDSAP256SHA256, 15 is
ED25519, etc.), and the key tag (12345 in this case). The private key (in
the ``.private`` file) is used to generate signatures, and the public
key (in the ``.key`` file) is used for signature verification.
To generate another key with the same properties but with a different
key tag, repeat the above command.
The :iscman:`dnssec-keyfromlabel` program is used to get a key pair from a
crypto hardware device and build the key files. Its usage is similar to
:iscman:`dnssec-keygen`.
The public keys should be inserted into the zone file by including the
``.key`` files using ``$INCLUDE`` statements.
.. _dnssec_zone_signing: .. _dnssec_zone_signing:
Signing the Zone Zone Signing
^^^^^^^^^^^^^^^^ ~~~~~~~~~~~~
The :iscman:`dnssec-signzone` program is used to sign a zone. BIND offers several ways to generate signatures and maintain their validity
during the lifetime of a DNS zone:
Any ``keyset`` files corresponding to secure sub-zones should be - :ref:`dnssec_kasp` - **strongly recommended**
present. The zone signer generates ``NSEC``, ``NSEC3``, and ``RRSIG`` - :ref:`dnssec_dynamic_zones` - only for special needs
records for the zone, as well as ``DS`` for the child zones if :option:`-g <dnssec-signzone -g>` - :ref:`dnssec_tools` - discouraged, use only for debugging
is specified. If :option:`-g <dnssec-signzone -g>` is not specified, then DS RRsets for the
secure child zones need to be added manually.
By default, all zone keys which have an available private key are used .. _zone_keys:
to generate signatures. The following command signs the zone, assuming
it is in a file called ``zone.child.example``:
``dnssec-signzone -o child.example zone.child.example`` Zone keys
^^^^^^^^^
Regardless of the :ref:`zone-signing <dnssec_zone_signing>` method in use, cryptographic keys are
stored in files named like :file:`Kdnssec.example.+013+12345.key` and
:file:`Kdnssec.example.+013+12345.private`.
The private key (in the ``.private`` file) is used to generate signatures, and
the public key (in the ``.key`` file) is used for signature verification.
Additionally, the :ref:`dnssec_kasp` method creates a third file,
:file:`Kdnssec.example+013+12345.state`, which is used to track DNSSEC key timings
and to perform key rollovers safely.
One output file is produced: ``zone.child.example.signed``. This file These filenames contain:
should be referenced by :iscman:`named.conf` as the input file for the zone.
:iscman:`dnssec-signzone` also produces keyset and dsset files. These are used - the key name, which always matches the zone name (``dnssec.example.``),
to provide the parent zone administrators with the ``DNSKEYs`` (or their - the `algorithm number`_ (013 is ECDSAP256SHA256, 008 is RSASHA256, etc.),
corresponding ``DS`` records) that are the secure entry point to the zone. - and the key tag, i.e. a non-unique key identifier (12345 in this case).
.. _dnssec_config: .. _`algorithm number`: https://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml#dns-sec-alg-numbers-1
Configuring Servers for DNSSEC
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
To enable :iscman:`named` to validate answers received from other servers, the .. warning::
``dnssec-validation`` option must be set to either ``yes`` or ``auto``. Private keys are required for full disaster recovery. Back up key files in a
safe location and protect them from unauthorized access. Anyone with
access to the private key can create fake but seemingly valid DNS data.
When ``dnssec-validation`` is set to ``auto``, a trust anchor for the
DNS root zone is automatically used. This trust anchor is provided
as part of BIND and is kept up to date using :rfc:`5011` key management.
When ``dnssec-validation`` is set to ``yes``, DNSSEC validation .. _dnssec_kasp:
only occurs if at least one trust anchor has been explicitly configured
in :iscman:`named.conf`, using a ``trust-anchors`` statement (or the
``managed-keys`` and ``trusted-keys`` statements, both deprecated).
When ``dnssec-validation`` is set to ``no``, DNSSEC validation does not Fully Automated (Key and Signing Policy)
occur. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The default is ``auto`` unless BIND is built with Key and Signing Policy (KASP) is a method of configuration that describes
``configure --disable-auto-validation``, in which case the default is how to maintain DNSSEC signing keys and how to sign the zone.
``yes``.
The keys specified in ``trust-anchors`` are copies of DNSKEY RRs for zones that are This is the recommended, fully automated way to sign and maintain DNS zones. For
used to form the first link in the cryptographic chain of trust. Keys configured most use cases users can simply use the built-in default policy, which applies
with the keyword ``static-key`` or ``static-ds`` are loaded directly into the up-to-date DNSSEC practices:
table of trust anchors, and can only be changed by altering the
configuration. Keys configured with ``initial-key`` or ``initial-ds`` are used
to initialize :rfc:`5011` trust anchor maintenance, and are kept up-to-date
automatically after the first time :iscman:`named` runs.
``trust-anchors`` is described in more detail later in this document. .. code-block:: none
:emphasize-lines: 4
BIND 9 does not verify signatures on load, so zone keys zone "dnssec.example" {
for authoritative zones do not need to be specified in the configuration type primary;
file. file "dnssec.example.db";
dnssec-policy default;
After DNSSEC is established, a typical DNSSEC configuration looks
something like the following. It has one or more public keys for the
root, which allows answers from outside the organization to be validated.
It also has several keys for parts of the namespace that the
organization controls. These are here to ensure that :iscman:`named` is immune
to compromised security in the DNSSEC components of parent zones.
::
trust-anchors {
/* Root Key */
"." initial-key 257 3 3 "BNY4wrWM1nCfJ+CXd0rVXyYmobt7sEEfK3clRbGaTwS
JxrGkxJWoZu6I7PzJu/E9gx4UC1zGAHlXKdE4zYIpRh
aBKnvcC2U9mZhkdUpd1Vso/HAdjNe8LmMlnzY3zy2Xy
4klWOADTPzSv9eamj8V18PHGjBLaVtYvk/ln5ZApjYg
hf+6fElrmLkdaz MQ2OCnACR817DF4BBa7UR/beDHyp
5iWTXWSi6XmoJLbG9Scqc7l70KDqlvXR3M/lUUVRbke
g1IPJSidmK3ZyCllh4XSKbje/45SKucHgnwU5jefMtq
66gKodQj+MiA21AfUVe7u99WzTLzY3qlxDhxYQQ20FQ
97S+LKUTpQcq27R7AT3/V5hRQxScINqwcz4jYqZD2fQ
dgxbcDTClU0CRBdiieyLMNzXG3";
/* Key for our organization's forward zone */
example.com. static-ds 54135 5 2 "8EF922C97F1D07B23134440F19682E7519ADDAE180E20B1B1EC52E7F58B2831D"
/* Key for our reverse zone. */
2.0.192.IN-ADDRPA.NET. static-key 257 3 5 "AQOnS4xn/IgOUpBPJ3bogzwc
xOdNax071L18QqZnQQQAVVr+i
LhGTnNGp3HoWQLUIzKrJVZ3zg
gy3WwNT6kZo6c0tszYqbtvchm
gQC8CzKojM/W16i6MG/eafGU3
siaOdS0yOI6BgPsw+YZdzlYMa
IJGf4M4dyoKIhzdZyQ2bYQrjy
Q4LB0lC7aOnsMyYKHHYeRvPxj
IQXmdqgOJGq+vsevG06zW+1xg
YJh9rCIfnm1GX/KMgxLPG2vXT
D/RnLX+D3T3UL7HJYHJhAZD5L
59VvjSPsZJHeDCUyWYrvPZesZ
DIRvhDD52SKvbheeTJUm6Ehkz
ytNN2SN96QRk8j/iI8ib";
}; };
options { This single line is sufficient to create the necessary signing keys, and generate
... ``DNSKEY``, ``RRSIG``, and ``NSEC`` records for the zone. BIND also takes
dnssec-validation yes; care of any DNSSEC maintenance for this zone, including replacing signatures
that are about to expire and managing :ref:`key_rollovers`.
.. note::
``dnssec-policy`` needs write access to the zone. Please see
:ref:`dnssec_policy` for more details about implications for zone storage.
The default policy creates one key that is used to sign the complete zone,
and uses ``NSEC`` to enable authenticated denial of existence (a secure way
to tell which records do not exist in a zone). This policy is recommended
and typically does not need to be changed.
If needed, a custom policy can be defined by adding a ``dnssec-policy`` statement
into the configuration:
.. code-block:: none
dnssec-policy "custom" {
dnskey-ttl 600;
keys {
ksk lifetime P1Y algorithm ecdsap384sha384;
zsk lifetime 60d algorithm ecdsap384sha384;
};
nsec3param iterations 0 optout no salt-length 0;
}; };
.. This ``custom`` policy, for example:
.. note:: - uses a very short ``DNSKEY`` TTL (600 seconds),
- uses two keys to sign the zone: a Key Signing Key (KSK) to sign the key
related RRsets (``DNSKEY``, ``CDS``, and ``CDNSKEY``), and a Zone Signing
Key (ZSK) to sign the rest of the zone. The KSK is automatically
rotated after one year and the ZSK after 60 days.
None of the keys listed in this example are valid. In particular, the Also:
root key is not valid. - The configured keys have a lifetime set and use the ECDSAP384SHA384
algorithm.
- The last line instructs BIND to generate NSEC3 records for
:ref:`Proof of Non-Existence <advanced_discussions_proof_of_nonexistence>`,
using zero extra iterations and no salt. NSEC3 opt-out is disabled, meaning
insecure delegations also get an NSEC3 record.
When DNSSEC validation is enabled and properly configured, the resolver For more information about KASP configuration see :ref:`dnssec_policy_grammar`.
rejects any answers from signed, secure zones which fail to
validate, and returns SERVFAIL to the client.
Responses may fail to validate for any of several reasons, including The :ref:`dnssec_advanced_discussions` section in the DNSSEC Guide discusses the
missing, expired, or invalid signatures, a key which does not match the various policy settings and may be useful for determining values for specific
DS RRset in the parent zone, or an insecure response from a zone which, needs.
according to its parent, should have been secure.
.. note:: Key Rollover
============
When the validator receives a response from an unsigned zone that has When using a ``dnssec-policy``, a key lifetime can be set to trigger
a signed parent, it must confirm with the parent that the zone was key rollovers. ZSK rollovers are fully automatic, but for KSK and CSK rollovers
intentionally left unsigned. It does this by verifying, via signed a DS record needs to be submitted to the parent. See
and validated NSEC/NSEC3 records, that the parent zone contains no DS :ref:`secure_delegation` for possible ways to do so.
records for the child.
If the validator *can* prove that the zone is insecure, then the Once the DS is in the parent (and the DS of the predecessor key is withdrawn),
response is accepted. However, if it cannot, the validator must assume an BIND needs to be told that this event has happened. This can be done automatically
insecure response to be a forgery; it rejects the response and logs by configuring parental agents:
an error.
The logged error reads "insecurity proof failed" and "got insecure .. code-block:: none
response; parent indicates it should be secure." :emphasize-lines: 5
zone "dnssec.example" {
type primary;
file "dnssec.example.db";
dnssec-policy default;
parental-agents { 192.0.2.1; };
};
Here one server, ``192.0.2.1``, is configured for BIND to send DS queries to,
to check the DS RRset for ``dnssec-example`` during key rollovers. This needs
to be a trusted server, because BIND does not validate the response.
If setting up a parental agent is undesirable, it is also possible to tell BIND that the
DS is published in the parent with:
:option:`rndc dnssec -checkds -key 12345 published dnssec.example. <rndc dnssec>`.
and the DS for the predecessor key has been removed with:
:option:`rndc dnssec -checkds -key 54321 withdrawn dnssec.example. <rndc dnssec>`.
where 12345 and 54321 are the key tags of the successor and predecessor key,
respectively.
To roll a key sooner than scheduled, or to roll a key that
has an unlimited lifetime, use:
:option:`rndc dnssec -rollover -key 12345 dnssec.example. <rndc dnssec>`.
To revert a signed zone back to an insecure zone, change
the zone configuration to use the built-in "insecure" policy. Detailed
instructions are described in :ref:`revert_to_unsigned`.
.. _dnssec_dynamic_zones: .. _dnssec_dynamic_zones:
DNSSEC, Dynamic Zones, and Automatic Signing Manual Key Management
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^^^^^^^^^^^^^^^^^^^^^
Converting From Insecure to Secure .. warning::
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The method described here allows full control over the keys used to sign
the zone. This is required only for very special cases and is generally
discouraged. Under normal circumstances, please use :ref:`dnssec_kasp`.
A zone can be changed from insecure to secure in three ways: using a
dynamic DNS update, via the ``auto-dnssec`` zone option, or by setting a
DNSSEC policy for the zone with ``dnssec-policy``.
For any method, :iscman:`named` must be configured so that it can see .. _dnssec_dynamic_zones_multisigner_model:
the ``K*`` files which contain the public and private parts of the keys
that are used to sign the zone. These files are generated Multi-Signer Model
by :iscman:`dnssec-keygen`, or created when needed by :iscman:`named` if ==================
``dnssec-policy`` is used. Keys should be placed in the
key-directory, as specified in :iscman:`named.conf`: Dynamic zones provide the ability to sign a zone by multiple providers, meaning
each provider signs and serves the same zone independently. Such a setup requires
some coordination between providers when it comes to key rollovers, and may be
better suited to be configured with ``auto-dnssec allow;``. This permits keys to
be updated and the zone to be re-signed only if the user issues the command
:option:`rndc sign zonename <rndc sign>`.
A zone can also be configured with ``auto-dnssec maintain``, which automatically
adjusts the zone's DNSSEC keys on a schedule according to the key timing
metadata. However, keys still need to be generated separately, for
example with :iscman:`dnssec-keygen`.
Of course, dynamic zones can also use ``dnssec-policy`` to fully automate DNSSEC
maintenance. The next sections assume that more key
management control is needed, and describe how to use dynamic DNS update to perform
various DNSSEC operations.
.. _dnssec_dynamic_zones_enabling_dnssec:
Enabling DNSSEC Manually
========================
As an alternative to fully automated zone signing using :ref:`dnssec-policy
<dnssec_kasp>`, a zone can be changed from insecure to secure using a dynamic
DNS update. :iscman:`named` must be configured so that it can see the ``K*``
files which contain the public and private parts of the `zone keys`_ that are
used to sign the zone. Key files should be placed in the ``key-directory``, as
specified in :iscman:`named.conf`:
:: ::
zone example.net { zone update.example {
type primary; type primary;
update-policy local; update-policy local;
file "dynamic/example.net/example.net"; auto-dnssec allow;
key-directory "dynamic/example.net"; file "dynamic/update.example.db";
key-directory "keys/update.example/";
}; };
If one KSK and one ZSK DNSKEY key have been generated, this If there are both a KSK and a ZSK available (or a CSK), this configuration causes the
configuration causes all records in the zone to be signed with the zone to be signed. An ``NSEC`` chain is generated as part of the initial signing
ZSK, and the DNSKEY RRset to be signed with the KSK. An NSEC process.
chain is generated as part of the initial signing process.
With ``dnssec-policy``, it is possible to specify which keys should be In any secure zone which supports dynamic updates, :iscman:`named` periodically
KSK and/or ZSK. To sign all records with a key, a CSK must be specified. re-signs RRsets which have not been re-signed as a result of some update action.
For example: The signature lifetimes are adjusted to spread the re-sign load over time rather
than all at once.
:: .. _dnssec_dynamic_zones_publishing_dnskey_records:
dnssec-policy csk { Publishing DNSKEY Records
keys { =========================
csk lifetime unlimited algorithm 13;
};
};
Dynamic DNS Update Method
^^^^^^^^^^^^^^^^^^^^^^^^^
To insert the keys via dynamic update: To insert the keys via dynamic update:
@@ -275,14 +268,17 @@ To insert the keys via dynamic update:
% nsupdate % nsupdate
> ttl 3600 > ttl 3600
> update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8= > update add update.example DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8=
> update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk= > update add update.example DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk=
> send > send
While the update request completes almost immediately, the zone is In order to sign with these keys, the corresponding key files should also be
not completely signed until :iscman:`named` has had time to "walk" the zone placed in the ``key-directory``.
and generate the NSEC and RRSIG records. The NSEC record at the apex
is added last, to signal that there is a complete NSEC chain. .. _dnssec_dynamic_zones_nsec3:
NSEC3
=====
To sign using :ref:`NSEC3 <advanced_discussions_nsec3>` instead of :ref:`NSEC To sign using :ref:`NSEC3 <advanced_discussions_nsec3>` instead of :ref:`NSEC
<advanced_discussions_nsec>`, add an NSEC3PARAM record to the initial update <advanced_discussions_nsec>`, add an NSEC3PARAM record to the initial update
@@ -294,88 +290,108 @@ NSEC3PARAM record.
% nsupdate % nsupdate
> ttl 3600 > ttl 3600
> update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8= > update add update.example DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8=
> update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk= > update add update.example DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk=
> update add example.net NSEC3PARAM 1 1 100 1234567890 > update add update.example NSEC3PARAM 1 0 0 -
> send > send
Again, this update request completes almost immediately; however, Note that the ``NSEC3PARAM`` record does not show up until :iscman:`named` has
the record does not show up until :iscman:`named` has had a chance to had a chance to build/remove the relevant chain. A private type record is
build/remove the relevant chain. A private type record is created created to record the state of the operation (see below for more details), and
to record the state of the operation (see below for more details), and
is removed once the operation completes. is removed once the operation completes.
While the initial signing and NSEC/NSEC3 chain generation is happening, The ``NSEC3`` chain is generated and the ``NSEC3PARAM`` record is added before
the ``NSEC`` chain is destroyed.
While the initial signing and ``NSEC``/``NSEC3`` chain generation are occurring,
other updates are possible as well. other updates are possible as well.
Fully Automatic Zone Signing A new ``NSEC3PARAM`` record can be added via dynamic update. When the new
^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ``NSEC3`` chain has been generated, the ``NSEC3PARAM`` flag field is set to
zero. At that point, the old ``NSEC3PARAM`` record can be removed. The old
chain is removed after the update request completes.
To enable automatic signing, set a ``dnssec-policy`` or add the :iscman:`named` only supports creating new ``NSEC3`` chains where all the
``auto-dnssec`` option to the zone statement in :iscman:`named.conf`. ``NSEC3`` records in the zone have the same ``OPTOUT`` state. :iscman:`named`
``auto-dnssec`` has two possible arguments: ``allow`` or ``maintain``. supports updates to zones where the ``NSEC3`` records in the chain have mixed
``OPTOUT`` state. :iscman:`named` does not support changing the ``OPTOUT``
state of an individual ``NSEC3`` record; if the ``OPTOUT`` state of an
individual ``NSEC3`` needs to be changed, the entire chain must be changed.
With ``auto-dnssec allow``, :iscman:`named` can search the key directory for To switch back to ``NSEC``, use :iscman:`nsupdate` to remove any ``NSEC3PARAM``
keys matching the zone, insert them into the zone, and use them to sign records. The ``NSEC`` chain is generated before the ``NSEC3`` chain is removed.
the zone. It does so only when it receives an
:option:`rndc sign zonename <rndc sign>`.
``auto-dnssec maintain`` includes the above functionality, but also .. _dnssec_dynamic_zones_dnskey_rollovers:
automatically adjusts the zone's DNSKEY records on a schedule according to
the keys' timing metadata. (See :ref:`man_dnssec-keygen` and
:ref:`man_dnssec-settime` for more information.)
``dnssec-policy`` is similar to ``auto-dnssec maintain``, but DNSKEY Rollovers
``dnssec-policy`` also automatically creates new keys when necessary. In ================
addition, any configuration related to DNSSEC signing is retrieved from the
policy, ignoring existing DNSSEC :iscman:`named.conf` options.
:iscman:`named` periodically searches the key directory for keys matching To perform key rollovers via a dynamic update, the ``K*`` files for the new keys
the zone; if the keys' metadata indicates that any change should be must be added so that :iscman:`named` can find them. The new ``DNSKEY`` RRs can
made to the zone - such as adding, removing, or revoking a key - then that then be added via dynamic update. When the zones are being signed, they are
action is carried out. By default, the key directory is checked for signed with the new key set; when the signing is complete, the private type
changes every 60 minutes; this period can be adjusted with records are updated so that the last octet is non-zero.
``dnssec-loadkeys-interval``, up to a maximum of 24 hours. The
:option:`rndc loadkeys` command forces :iscman:`named` to check for key updates immediately.
If keys are present in the key directory the first time the zone is If this is for a KSK, the parent and any trust anchor repositories of the new
loaded, the zone is signed immediately, without waiting for an KSK must be informed.
:option:`rndc sign` or :option:`rndc loadkeys` command. Those commands can still be
used when there are unscheduled key changes.
When new keys are added to a zone, the TTL is set to match that of any The maximum TTL in the zone must expire before removing the old ``DNSKEY``. If
existing DNSKEY RRset. If there is no existing DNSKEY RRset, the it is a KSK that is being updated, the DS RRset in the parent must also be
TTL is set to the TTL specified when the key was created (using the updated and its TTL allowed to expire. This ensures that all clients are able to
:option:`dnssec-keygen -L` option), if any, or to the SOA TTL. verify at least one signature when the old ``DNSKEY`` is removed.
To sign the zone using NSEC3 instead of NSEC, submit an The old ``DNSKEY`` can be removed via ``UPDATE``, taking care to specify the
NSEC3PARAM record via dynamic update prior to the scheduled publication correct key. :iscman:`named` cleans out any signatures generated by the old
and activation of the keys. The OPTOUT bit for the NSEC3 chain can be set key after the update completes.
in the flags field of the NSEC3PARAM record. The
NSEC3PARAM record does not appear in the zone immediately, but it is
stored for later reference. When the zone is signed and the NSEC3
chain is completed, the NSEC3PARAM record appears in the zone.
Using the ``auto-dnssec`` option requires the zone to be configured to .. _dnssec_dynamic_zones_going_insecure:
allow dynamic updates, by adding an ``allow-update`` or
``update-policy`` statement to the zone configuration. If this has not
been done, the configuration fails.
Private Type Records Going Insecure
^^^^^^^^^^^^^^^^^^^^ ==============
The state of the signing process is signaled by private type records To convert a signed zone to unsigned using dynamic DNS, delete all the
(with a default type value of 65534). When signing is complete, those ``DNSKEY`` records from the zone apex using :iscman:`nsupdate`. All signatures,
records with a non-zero initial octet have a non-zero value for the final octet. ``NSEC`` or ``NSEC3`` chains, and associated ``NSEC3PARAM`` records are removed
automatically when the zone is supposed to be re-signed.
If the first octet of a private type record is non-zero, the This requires the ``dnssec-secure-to-insecure`` option to be set to ``yes`` in
record indicates either that the zone needs to be signed with the key matching :iscman:`named.conf`.
the record, or that all signatures that match the record should be
removed. Here are the meanings of the different values of the first octet: In addition, if the ``auto-dnssec maintain`` or a ``dnssec-policy`` is used, it
should be removed or changed to ``allow`` instead; otherwise it will re-sign.
.. _dnssec_tools:
Manual Signing
^^^^^^^^^^^^^^
There are several tools available to manually sign a zone.
.. warning::
Please note manual procedures are available mainly for backwards
compatibility and should be used only by expert users with specific needs.
To set up a DNSSEC secure zone manually, a series of steps
must be followed. Please see chapter
:ref:`advanced_discussions_manual_key_management_and_signing` in the
:doc:`dnssec-guide` for more information.
Monitoring with Private Type Records
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The state of the signing process is signaled by private type records (with a
default type value of 65534). When signing is complete, those records with a
non-zero initial octet have a non-zero value for the final octet.
If the first octet of a private type record is non-zero, the record indicates
either that the zone needs to be signed with the key matching the record, or
that all signatures that match the record should be removed. Here are the
meanings of the different values of the first octet:
- algorithm (octet 1) - algorithm (octet 1)
- key id in network order (octet 2 and 3) - key ID in network order (octet 2 and 3)
- removal flag (octet 4) - removal flag (octet 4)
@@ -384,11 +400,11 @@ removed. Here are the meanings of the different values of the first octet:
Only records flagged as "complete" can be removed via dynamic update; attempts Only records flagged as "complete" can be removed via dynamic update; attempts
to remove other private type records are silently ignored. to remove other private type records are silently ignored.
If the first octet is zero (this is a reserved algorithm number that If the first octet is zero (this is a reserved algorithm number that should
should never appear in a DNSKEY record), the record indicates that never appear in a ``DNSKEY`` record), the record indicates that changes to the
changes to the NSEC3 chains are in progress. The rest of the record ``NSEC3`` chains are in progress. The rest of the record contains an
contains an NSEC3PARAM record, while the flag field tells what operation to ``NSEC3PARAM`` record, while the flag field tells what operation to perform
perform based on the flag bits: based on the flag bits:
0x01 OPTOUT 0x01 OPTOUT
@@ -398,106 +414,103 @@ perform based on the flag bits:
0x20 NONSEC 0x20 NONSEC
DNSKEY Rollovers .. _secure_delegation:
^^^^^^^^^^^^^^^^
As with insecure-to-secure conversions, DNSSEC keyrolls can be done Secure Delegation
in two ways: using a dynamic DNS update, or via the ``auto-dnssec`` zone ~~~~~~~~~~~~~~~~~
option.
Dynamic DNS Update Method Once a zone is signed on the authoritative servers, the last remaining step
^^^^^^^^^^^^^^^^^^^^^^^^^ is to establish chain of trust [#validation]_ between the parent zone
(``example.``) and the local zone (``dnssec.example.``).
To perform key rollovers via a dynamic update, the ``K*`` Generally the procedure is:
files for the new keys must be added so that :iscman:`named` can find them.
The new DNSKEY RRs can then be added via dynamic update. :iscman:`named` then causes the
zone to be signed with the new keys; when the signing is complete, the
private type records are updated so that the last octet is non-zero.
If this is for a KSK, the parent and any trust anchor - **Wait** for stale data to expire from caches. The amount of time required
repositories of the new KSK must be informed. is equal to the maximum TTL value used in the zone before signing. This
step ensures that unsigned data expire from caches and resolvers do not get
confused by missing signatures.
- Insert/update DS records in the parent zone (``dnssec.example. DS`` record).
The maximum TTL in the zone must expire before removing the There are multiple ways to update DS records in the parent zone. Refer to the
old DNSKEY. If it is a KSK that is being updated, documentation for the parent zone to find out which options are applicable to
the DS RRset in the parent must also be updated and its TTL allowed to expire. This a given case zone. Generally the options are, from most- to least-recommended:
ensures that all clients are able to verify at least one signature
when the old DNSKEY is removed.
The old DNSKEY can be removed via UPDATE, taking care to specify the - Automatically update the DS record in the parent zone using
correct key. :iscman:`named` cleans out any signatures generated by the ``CDS``/``CDNSKEY`` records automatically generated by BIND. This requires
old key after the update completes. support for :rfc:`7344` in either parent zone, registry, or registrar. In
that case, configure BIND to :ref:`monitor DS records in the parent
zone <cds_cdnskey>` and everything will happen automatically at the right
time.
- Query the zone for automatically generated ``CDS`` or ``CDNSKEY`` records using
:iscman:`dig`, and then insert these records into the parent zone using
the method specified by the parent zone (web form, e-mail, API, ...).
- Generate DS records manually using the :iscman:`dnssec-dsfromkey` utility on
`zone keys`_, and then insert them into the parent zone.
Automatic Key Rollovers .. [#validation] For further details on how the chain of trust is used in practice, see
^^^^^^^^^^^^^^^^^^^^^^^ :ref:`dnssec_12_steps` in the :doc:`dnssec-guide`.
When a new key reaches its activation date (as set by :iscman:`dnssec-keygen`
or :iscman:`dnssec-settime`), and if the ``auto-dnssec`` zone option is set to
``maintain``, :iscman:`named` automatically carries out the key rollover.
If the key's algorithm has not previously been used to sign the zone,
then the zone is fully signed as quickly as possible. However, if
the new key replaces an existing key of the same algorithm, the
zone is re-signed incrementally, with signatures from the old key
replaced with signatures from the new key as their signature
validity periods expire. By default, this rollover completes in 30 days,
after which it is safe to remove the old key from the DNSKEY RRset.
NSEC3PARAM Rollovers via UPDATE
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The new NSEC3PARAM record can be added via dynamic update. When the new NSEC3 DNSSEC Validation
chain has been generated, the NSEC3PARAM flag field is set to zero. At ~~~~~~~~~~~~~~~~~
that point, the old NSEC3PARAM record can be removed. The old chain is
removed after the update request completes.
Converting From NSEC to NSEC3 The BIND resolver validates answers from authoritative servers by default. This
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ behavior is controlled by the configuration statement :ref:`dnssec-validation
<dnssec-validation-option>`.
Add a ``nsec3param`` option to your ``dnssec-policy`` and By default a trust anchor for the DNS root zone is used.
run :option:`rndc reconfig`. This trust anchor is provided as part of BIND and is kept up-to-date using
:ref:`rfc5011.support`.
Or use :iscman:`nsupdate` to add an NSEC3PARAM record. .. note::
DNSSEC validation works "out of the box" and does not require
additional configuration. Additional configuration options are intended only
for special cases.
In both cases, the NSEC3 chain is generated and the NSEC3PARAM record is To validate answers, the resolver needs at least one trusted starting point,
added before the NSEC chain is destroyed. a "trust anchor." Essentially, trust anchors are copies of ``DNSKEY`` RRs for
zones that are used to form the first link in the cryptographic chain of trust.
Alternative trust anchors can be specified using :ref:`trust_anchors`, but
this setup is very unusual and is recommended only for expert use.
For more information, see :ref:`trust_anchors_description` in the
:doc:`dnssec-guide`.
Converting From NSEC3 to NSEC The BIND authoritative server does not verify signatures on load, so zone keys
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ for authoritative zones do not need to be specified in the configuration
file.
To do this, remove the ``nsec3param`` option from the ``dnssec-policy`` and Validation Failures
run :option:`rndc reconfig`.
Or use :iscman:`nsupdate` to remove all NSEC3PARAM records with a
zero flag field. The NSEC chain is generated before the NSEC3 chain
is removed.
Converting From Secure to Insecure
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
To convert a signed zone to unsigned using dynamic DNS, delete all the
DNSKEY records from the zone apex using :iscman:`nsupdate`. All signatures,
NSEC or NSEC3 chains, and associated NSEC3PARAM records are removed
automatically. This takes place after the update request completes.
This requires the ``dnssec-secure-to-insecure`` option to be set to
``yes`` in :iscman:`named.conf`.
In addition, if the ``auto-dnssec maintain`` zone statement is used, it
should be removed or changed to ``allow`` instead; otherwise it will re-sign.
Periodic Re-signing
^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^
In any secure zone which supports dynamic updates, :iscman:`named` When DNSSEC validation is configured, the resolver rejects any answers from
periodically re-signs RRsets which have not been re-signed as a result of signed, secure zones which fail to validate, and returns SERVFAIL to the
some update action. The signature lifetimes are adjusted to client.
spread the re-sign load over time rather than all at once.
NSEC3 and OPTOUT Responses may fail to validate for any of several reasons, including
^^^^^^^^^^^^^^^^ missing, expired, or invalid signatures; a key which does not match the
DS RRset in the parent zone; or an insecure response from a zone which,
according to its parent, should have been secure.
:iscman:`named` only supports creating new NSEC3 chains where all the NSEC3 For more information see :ref:`dnssec_troubleshooting`.
records in the zone have the same OPTOUT state. :iscman:`named` supports
UPDATES to zones where the NSEC3 records in the chain have mixed OPTOUT Coexistence With Unsigned (Insecure) Zones
state. :iscman:`named` does not support changing the OPTOUT state of an ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
individual NSEC3 record; if the
OPTOUT state of an individual NSEC3 needs to be changed, the entire chain must be changed. Zones not protected by DNSSEC are called "insecure," and these zones seamlessly
coexist with signed zones.
When the validator receives a response from an unsigned zone that has
a signed parent, it must confirm with the parent that the zone was
intentionally left unsigned. It does this by verifying, via signed
and validated :ref:`NSEC/NSEC3 records
<advanced_discussions_proof_of_nonexistence>`, that the parent zone contains no
DS records for the child.
If the validator *can* prove that the zone is insecure, then the
response is accepted. However, if it cannot, the validator must assume an
insecure response to be a forgery; it rejects the response and logs
an error.
The logged error reads "insecurity proof failed" and "got insecure
response; parent indicates it should be secure."

4
doc/arm/reference.rst
View File

@@ -2114,7 +2114,9 @@ Boolean Options
This option enables DNSSEC validation in :iscman:`named`. This option enables DNSSEC validation in :iscman:`named`.
If set to ``auto``, DNSSEC validation is enabled and a default trust If set to ``auto``, DNSSEC validation is enabled and a default trust
anchor for the DNS root zone is used. anchor for the DNS root zone is used. This trust anchor is provided
as part of BIND and is kept up-to-date using :ref:`rfc5011.support` key
management.
If set to ``yes``, DNSSEC validation is enabled, but a trust anchor must be If set to ``yes``, DNSSEC validation is enabled, but a trust anchor must be
manually configured using a ``trust-anchors`` statement (or the manually configured using a ``trust-anchors`` statement (or the

91
doc/dnssec-guide/recipes.rst
View File

@@ -986,12 +986,40 @@ Reverting to Unsigned
This recipe describes how to revert from a signed zone (DNSSEC) back to This recipe describes how to revert from a signed zone (DNSSEC) back to
an unsigned (DNS) zone. an unsigned (DNS) zone.
Whether the world thinks your zone is signed is determined by the Here is what :iscman:`named.conf` looks like when it is signed:
presence of DS records hosted by your parent zone; if there are no DS records,
the world sees your zone as unsigned. So reverting to unsigned is as
easy as removing all DS records from the parent zone.
Below is an example showing how to remove DS records using the .. code-block:: none
:emphasize-lines: 4
zone "example.com" IN {
type primary;
file "db/example.com.db";
dnssec-policy "default";
};
To indicate the reversion to unsigned, change the ``dnssec-policy`` line:
.. code-block:: none
:emphasize-lines: 4
zone "example.com" IN {
type primary;
file "db/example.com.db";
dnssec-policy "insecure";
};
Then use :option:`rndc reload` to reload the zone.
The "insecure" policy is a built-in policy (like "default"). It makes sure
the zone is still DNSSEC-maintained, to allow for a graceful transition to
unsigned. It also publishes the CDS and CDNSKEY DELETE records automatically
at the appropriate time.
If the parent zone allows management of DS records via CDS/CDNSKEY, as described in
:rfc:`8078`, the DS record should be removed from the parent automatically.
Otherwise, DS records can be removed via the registrar. Below is an example
showing how to remove DS records using the
`GoDaddy <https://www.godaddy.com>`__ web-based interface: `GoDaddy <https://www.godaddy.com>`__ web-based interface:
1. After logging in, click the green "Launch" button next to the domain 1. After logging in, click the green "Launch" button next to the domain
@@ -1036,58 +1064,17 @@ Below is an example showing how to remove DS records using the
Revert to Unsigned Step #4 Revert to Unsigned Step #4
If your parent allows managing DS record via CDS/CDNSKEY, as described in
:rfc:`5155`, you could add CDS/CDNSKEY DELETE records in your zone to signal
that the corresponding DS records from the parent zone needs to be removed.
If it is unclear which format the parent zone is expecting, you should publish
both CDS and CDNSKEY DELETE records.
To be on the safe side, wait a while before actually deleting
all signed data from your zone, just in case some validating resolvers
have cached information. After you are certain that all cached
information has expired (usually this means one TTL interval has passed),
you may reconfigure your zone.
Here is what :iscman:`named.conf` looks like when it is signed:
::
zone "example.com" IN {
type primary;
file "db/example.com.db";
allow-transfer { any; };
dnssec-policy "default";
};
Change your ``dnssec-policy`` line to indicate you want to revert to unsigned:
::
zone "example.com" IN {
type primary;
file "db/example.com.db";
allow-transfer { any; };
dnssec-policy "insecure";
};
Then use :option:`rndc reload` to reload the zone.
The "insecure" policy is a built-in policy (like "default"). It will make sure
the zone is still DNSSEC maintained, to allow for a graceful transition to
unsigned. It also publishes the CDS and CDNSKEY DELETE records for you when
the time is right.
When the DS records have been removed from the parent zone, use When the DS records have been removed from the parent zone, use
:option:`rndc dnssec -checkds -key id withdrawn example.com <rndc dnssec>` to tell :iscman:`named` that :option:`rndc dnssec -checkds -key id withdrawn example.com <rndc dnssec>` to tell :iscman:`named` that
the DS is removed, and the remaining DNSSEC records will be removed in a timely the DS is removed, and the remaining DNSSEC records will be removed in a timely
manner. Or if you have parental agents configured, the DNSSEC records will be manner. Or, if parental agents are configured, the DNSSEC records will be
automatically removed after BIND has seen that the parental agents no longer automatically removed after BIND has seen that the parental agents no longer
serves the DS RRset for this zone. serve the DS RRset for this zone.
After a while, your zone is reverted back to the traditional, insecure DNS After a while, the zone is reverted back to the traditional, insecure DNS
format. You can verify by checking that all DNSKEY and RRSIG records have been format. This can be verified by checking that all DNSKEY and RRSIG records have been
removed from the zone. removed from the zone.
You can then remove the ``dnssec-policy`` line from your :iscman:`named.conf` and The ``dnssec-policy`` line can then be removed from :iscman:`named.conf` and
reload the zone. The zone will now no longer be subject to any DNSSEC the zone reloaded. The zone will no longer be subject to any DNSSEC
maintenance. maintenance.

115
doc/dnssec-guide/signing.rst
View File

@@ -1098,25 +1098,25 @@ Generate Keys
Everything in DNSSEC centers around keys, so we begin by Everything in DNSSEC centers around keys, so we begin by
generating our own keys. generating our own keys.
:: .. code-block:: console
# cd /etc/bind # cd /etc/bind/keys
# dnssec-keygen -a RSASHA256 -b 1024 example.com # dnssec-keygen -a ECDSAP256SHA256 example.com
Generating key pair...........................+++++ ......................+++++ Generating key pair...........................+++++ ......................+++++
Kexample.com.+008+34371 Kexample.com.+013+34371
# dnssec-keygen -a RSASHA256 -b 2048 -f KSK example.com # dnssec-keygen -a ECDSAP256SHA256 -f KSK example.com
Generating key pair........................+++ ..................................+++ Generating key pair........................+++ ..................................+++
Kexample.com.+008+00472 Kexample.com.+013+00472
This command generates four key files in ``/etc/bind/keys``: This command generates four key files in ``/etc/bind/keys``:
- Kexample.com.+008+34371.key - Kexample.com.+013+34371.key
- Kexample.com.+008+34371.private - Kexample.com.+013+34371.private
- Kexample.com.+008+00472.key - Kexample.com.+013+00472.key
- Kexample.com.+008+00472.private - Kexample.com.+013+00472.private
The two files ending in ``.key`` are the public keys. These contain the The two files ending in ``.key`` are the public keys. These contain the
DNSKEY resource records that appear in the zone. The two files DNSKEY resource records that appear in the zone. The two files
@@ -1127,41 +1127,35 @@ Of the two pairs, one is the zone-signing key (ZSK), and one is the
key-signing key (KSK). We can tell which is which by looking at the file key-signing key (KSK). We can tell which is which by looking at the file
contents (the actual keys are shortened here for ease of display): contents (the actual keys are shortened here for ease of display):
:: .. code-block:: console
# cat Kexample.com.+008+34371.key # cat Kexample.com.+013+34371.key
; This is a zone-signing key, keyid 34371, for example.com. ; This is a zone-signing key, keyid 34371, for example.com.
; Created: 20200616104249 (Tue Jun 16 11:42:49 2020) ; Created: 20200616104249 (Tue Jun 16 11:42:49 2020)
; Publish: 20200616104249 (Tue Jun 16 11:42:49 2020) ; Publish: 20200616104249 (Tue Jun 16 11:42:49 2020)
; Activate: 20200616104249 (Tue Jun 16 11:42:49 2020) ; Activate: 20200616104249 (Tue Jun 16 11:42:49 2020)
example.com. IN DNSKEY 256 3 8 AwEAAfel66...LqkA7cvn8= example.com. IN DNSKEY 256 3 13 AwEAAfel66...LqkA7cvn8=
# cat Kexample.com.+008+00472.key # cat Kexample.com.+013+00472.key
; This is a key-signing key, keyid 472, for example.com. ; This is a key-signing key, keyid 472, for example.com.
; Created: 20200616104254 (Tue Jun 16 11:42:54 2020) ; Created: 20200616104254 (Tue Jun 16 11:42:54 2020)
; Publish: 20200616104254 (Tue Jun 16 11:42:54 2020) ; Publish: 20200616104254 (Tue Jun 16 11:42:54 2020)
; Activate: 20200616104254 (Tue Jun 16 11:42:54 2020) ; Activate: 20200616104254 (Tue Jun 16 11:42:54 2020)
example.com. IN DNSKEY 257 3 8 AwEAAbCR6U...l8xPjokVU= example.com. IN DNSKEY 257 3 13 AwEAAbCR6U...l8xPjokVU=
The first line of each file tells us what type of key it is. Also, by The first line of each file tells us what type of key it is. Also, by
looking at the actual DNSKEY record, we can tell them apart: 256 is looking at the actual DNSKEY record, we can tell them apart: 256 is
ZSK, and 257 is KSK. ZSK, and 257 is KSK.
The name of the file also tells us something The name of the file also tells us something
about the contents. The file names are of the form: about the contents. See chapter :ref:`zone_keys` for more details.
:: Make sure that these files are readable by :iscman:`named` and that the
K<zone-name>+<algorithm-id>+<keyid>
The "zone name" is self-explanatory. The "algorithm ID" is a number assigned
to the algorithm used to construct the key: the number appears in the
DNSKEY resource record. In
our example, 8 means the algorithm RSASHA256. Finally, the "keyid" is
essentially a hash of the key itself.
Make sure these files are readable by :iscman:`named` and make sure that the
``.private`` files are not readable by anyone else. ``.private`` files are not readable by anyone else.
Alternativelly, the :iscman:`dnssec-keyfromlabel` program is used to get a key
pair from a crypto hardware device and build the key files. Its usage is
similar to :iscman:`dnssec-keygen`.
Setting Key Timing Information Setting Key Timing Information
++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++
@@ -1179,15 +1173,15 @@ the zone on 1 July 2020, use it to sign records for a year starting on
15 July 2020, and remove it from the zone at the end of July 2021, we 15 July 2020, and remove it from the zone at the end of July 2021, we
can use the following command: can use the following command:
:: .. code-block:: console
# dnssec-settime -P 20200701 -A 20200715 -I 20210715 -D 20210731 Kexample.com.+008+34371.key # dnssec-settime -P 20200701 -A 20200715 -I 20210715 -D 20210731 Kexample.com.+013+34371.key
./Kexample.com.+008+34371.key ./Kexample.com.+013+34371.key
./Kexample.com.+008+34371.private ./Kexample.com.+013+34371.private
which would set the contents of the key file to: which would set the contents of the key file to:
:: .. code-block:: none
; This is a zone-signing key, keyid 34371, for example.com. ; This is a zone-signing key, keyid 34371, for example.com.
; Created: 20200616104249 (Tue Jun 16 11:42:49 2020) ; Created: 20200616104249 (Tue Jun 16 11:42:49 2020)
@@ -1195,7 +1189,7 @@ which would set the contents of the key file to:
; Activate: 20200715000000 (Wed Jul 15 01:00:00 2020) ; Activate: 20200715000000 (Wed Jul 15 01:00:00 2020)
; Inactive: 20210715000000 (Thu Jul 15 01:00:00 2021) ; Inactive: 20210715000000 (Thu Jul 15 01:00:00 2021)
; Delete: 20210731000000 (Sat Jul 31 01:00:00 2021) ; Delete: 20210731000000 (Sat Jul 31 01:00:00 2021)
example.com. IN DNSKEY 256 3 8 AwEAAfel66...LqkA7cvn8= example.com. IN DNSKEY 256 3 13 AwEAAfel66...LqkA7cvn8=
(The actual key is truncated here to improve readability.) (The actual key is truncated here to improve readability.)
@@ -1381,19 +1375,38 @@ including interaction with the parent. A user certainly can do all this,
but why not use one of the automated methods? Nevertheless, it may but why not use one of the automated methods? Nevertheless, it may
be useful for test purposes, so we cover it briefly here. be useful for test purposes, so we cover it briefly here.
The first step is to create the keys as described in :ref:`generate_keys`. BIND 9 ships with several tools that are used in
Then, edit the zone file to make sure this process, which are explained in more detail below. In all cases,
the proper DNSKEY entries are included in your zone file. Finally, use the the ``-h`` option prints a full list of parameters. Note that the DNSSEC
command :iscman:`dnssec-signzone`: tools require the keyset files to be in the working directory or the
directory specified by the ``-d`` option.
:: The first step is to create the keys as described in :ref:`generate_keys`.
Then, edit the zone file to make sure the proper DNSKEY entries are included.
The public keys should be inserted into the zone file by
including the ``.key`` files using ``$INCLUDE`` statements.
Finally, use the command :iscman:`dnssec-signzone`.
Any ``keyset`` files corresponding to secure sub-zones should be
present. The zone signer generates ``NSEC``, ``NSEC3``, and ``RRSIG``
records for the zone, as well as ``DS`` for the child zones if
:option:`-g <dnssec-signzone -g>` is specified. If
:option:`-g <dnssec-signzone -g>` is not specified, then DS RRsets for the
secure child zones need to be added manually.
By default, all zone keys which have an available private key are used
to generate signatures. The following command signs the zone, assuming
it is in a file called ``zone.child.example``, using manually specified keys:
.. code-block:: console
# cd /etc/bind/keys/example.com/ # cd /etc/bind/keys/example.com/
# dnssec-signzone -A -t -N INCREMENT -o example.com -f /etc/bind/db/example.com.signed.db \ # dnssec-signzone -A -t -N INCREMENT -o example.com -f /etc/bind/db/example.com.signed.db \
> /etc/bind/db/example.com.db Kexample.com.+008+17694.key Kexample.com.+008+06817.key > /etc/bind/db/example.com.db Kexample.com.+013+17694.key Kexample.com.+013+06817.key
Verifying the zone using the following algorithms: RSASHA256. Verifying the zone using the following algorithms: ECDSAP256SHA256.
Zone fully signed: Zone fully signed:
Algorithm: RSASHA256: KSKs: 1 active, 0 stand-by, 0 revoked Algorithm: ECDSAP256SHA256: KSKs: 1 active, 0 stand-by, 0 revoked
ZSKs: 1 active, 0 stand-by, 0 revoked ZSKs: 1 active, 0 stand-by, 0 revoked
/etc/bind/db/example.com.signed.db /etc/bind/db/example.com.signed.db
Signatures generated: 17 Signatures generated: 17
@@ -1405,17 +1418,21 @@ command :iscman:`dnssec-signzone`:
Signatures per second: 364.634 Signatures per second: 364.634
Runtime in seconds: 0.055 Runtime in seconds: 0.055
The -o switch explicitly defines the domain name (``example.com`` in The :option:`-o <dnssec-signzone -o>` switch explicitly defines the domain name
this case), while the -f switch specifies the output file name. The second line (``example.com`` in this case), while the :option:`-f <dnssec-signzone -f>`
has three parameters: the unsigned zone name switch specifies the output file name. The second line has three parameters:
(``/etc/bind/db/example.com.db``), the ZSK file name, and the KSK file name. This the unsigned zone name (``/etc/bind/db/example.com.db``), the ZSK file name,
also generates a plain text file ``/etc/bind/db/example.com.signed.db``, and the KSK file name. This also generates a plain-text file
which you can verify for correctness. ``/etc/bind/db/example.com.signed.db``, which can be manually verified for correctness.
Finally, you'll need to update :iscman:`named.conf` to load the signed version :iscman:`dnssec-signzone` also produces keyset and dsset files. These are used
to provide the parent zone administrators with the ``DNSKEY`` records (or their
corresponding ``DS`` records) that are the secure entry point to the zone.
Finally, :iscman:`named.conf` needs to be updated to load the signed version
of the zone, which looks something like this: of the zone, which looks something like this:
:: .. code-block:: none
zone "example.com" IN { zone "example.com" IN {
type primary; type primary;