DNSSEC-SIGNZONE(1) BIND 9 DNSSEC-SIGNZONE(1)
NAME
dnssec-signzone - DNSSEC zone signing tool
SYNOPSIS
dnssec-signzone [-a] [-c class] [-d directory] [-D] [-E engine] [-e
end-time] [-f output-file] [-F] [-g] [-G sync-records] [-h] [-i inter-
val] [-I input-format] [-j jitter] [-J filename] [-K directory] [-k key]
[-L serial] [-M maxttl] [-N soa-serial-format] [-o origin] [-O out-
put-format] [-P] [-Q] [-q] [-R] [-S] [-s start-time] [-T ttl] [-t] [-u]
[-v level] [-V] [-X extended end-time] [-x] [-z] [-3 salt] [-H itera-
tions] [-A] {zonefile} [key...]
DESCRIPTION
dnssec-signzone signs a zone; it generates NSEC and RRSIG records and
produces a signed version of the zone. The security status of delega-
tions from the signed zone (that is, whether the child zones are secure)
is determined by the presence or absence of a keyset file for each child
zone.
OPTIONS
-a This option verifies all generated signatures.
-c class
This option specifies the DNS class of the zone.
-C This option sets compatibility mode, in which a keyset-zonename
file is generated in addition to dsset-zonename when signing a
zone, for use by older versions of dnssec-signzone.
-d directory
This option indicates the directory where BIND 9 should look for
dsset- or keyset- files.
-D This option indicates that only those record types automatically
managed by dnssec-signzone, i.e., RRSIG, NSEC, NSEC3 and
NSEC3PARAM records, should be included in the output. If smart
signing (-S) is used, DNSKEY records are also included. The re-
sulting file can be included in the original zone file with $IN-
CLUDE. This option cannot be combined with -O raw or serial-num-
ber updating.
-E engine
This option specifies the hardware to use for cryptographic oper-
ations, such as a secure key store used for signing, when applic-
able.
When BIND 9 is built with OpenSSL, this needs to be set to the
OpenSSL engine identifier that drives the cryptographic accelera-
tor or hardware service module (usually pkcs11).
-F This options turns on FIPS (US Federal Information Processing
Standards) mode if the underlying crytographic library supports
running in FIPS mode.
-g This option indicates that DS records for child zones should be
generated from a dsset- or keyset- file. Existing DS records are
removed.
-G sync-records
This option indicates which CDS and CDNSKEY records should be
generated. sync-records is a comma-separated string with the fol-
lowing allowed items: cdnskey, and cds:<digest-type>, where di-
gest-type is an allowed algorithm such as SHA-256 (2), or SHA-384
(4). Only works in combination with smart signing (-S).
-J filename
This option tells dnssec-signzone to read the journal from the
given file when loading the zone file.
-K directory
This option specifies the directory to search for DNSSEC keys. If
not specified, it defaults to the current directory.
-k key This option tells BIND 9 to treat the specified key as a
key-signing key, ignoring any key flags. This option may be spec-
ified multiple times.
-M maxttl
This option sets the maximum TTL for the signed zone. Any TTL
higher than maxttl in the input zone is reduced to maxttl in the
output. This provides certainty as to the largest possible TTL in
the signed zone, which is useful to know when rolling keys. The
maxttl is the longest possible time before signatures that have
been retrieved by resolvers expire from resolver caches. Zones
that are signed with this option should be configured to use a
matching max-zone-ttl in named.conf <#std-iscman-named.conf>.
(Note: This option is incompatible with -D, because it modifies
non-DNSSEC data in the output zone.)
-s start-time
This option specifies the date and time when the generated RRSIG
records become valid. This can be either an absolute or relative
time. An absolute start time is indicated by a number in YYYYMMD-
DHHMMSS notation; 20000530144500 denotes 14:45:00 UTC on May
30th, 2000. A relative start time is indicated by +N, which is N
seconds from the current time. If no start-time is specified, the
current time minus 1 hour (to allow for clock skew) is used.
-e end-time
This option specifies the date and time when the generated RRSIG
records expire. As with start-time, an absolute time is indicated
in YYYYMMDDHHMMSS notation. A time relative to the start time is
indicated with +N, which is N seconds from the start time. A time
relative to the current time is indicated with now+N. If no
end-time is specified, 30 days from the start time is the de-
fault. end-time must be later than start-time.
-X extended end-time
This option specifies the date and time when the generated RRSIG
records for the DNSKEY RRset expire. This is to be used in cases
when the DNSKEY signatures need to persist longer than signatures
on other records; e.g., when the private component of the KSK is
kept offline and the KSK signature is to be refreshed manually.
As with end-time, an absolute time is indicated in YYYYMMDDHHMMSS
notation. A time relative to the start time is indicated with +N,
which is N seconds from the start time. A time relative to the
current time is indicated with now+N. If no extended end-time is
specified, the value of end-time is used as the default.
(end-time, in turn, defaults to 30 days from the start time.) ex-
tended end-time must be later than start-time.
-f output-file
This option indicates the name of the output file containing the
signed zone. The default is to append .signed to the input file-
name. If output-file is set to -, then the signed zone is written
to the standard output, with a default output format of full.
-h This option prints a short summary of the options and arguments
to dnssec-signzone.
-V This option prints version information.
-i interval
This option indicates that, when a previously signed zone is
passed as input, records may be re-signed. The interval option
specifies the cycle interval as an offset from the current time,
in seconds. If a RRSIG record expires after the cycle interval,
it is retained; otherwise, it is considered to be expiring soon
and it is replaced.
The default cycle interval is one quarter of the difference be-
tween the signature end and start times. So if neither end-time
nor start-time is specified, dnssec-signzone generates signatures
that are valid for 30 days, with a cycle interval of 7.5 days.
Therefore, if any existing RRSIG records are due to expire in
less than 7.5 days, they are replaced.
Note that the calculation of cycle interval is based upon the va-
lidity period of the replacement signatures that would be gener-
ated by dnssec-signzone, not on the valid lifetimes of the input
RRSIGs being considered for pre-expiry replacement.
-I input-format
This option sets the format of the input zone file. Possible for-
mats are text (the default), and raw. This option is primarily
intended to be used for dynamic signed zones, so that the dumped
zone file in a non-text format containing updates can be signed
directly. This option is not useful for non-dynamic zones.
-j jitter
When signing a zone with a fixed signature lifetime, all RRSIG
records issued at the time of signing expire simultaneously. If
the zone is incrementally signed, i.e., a previously signed zone
is passed as input to the signer, all expired signatures must be
regenerated at approximately the same time. The jitter option
specifies a jitter window that is used to randomize the signature
expire time, thus spreading incremental signature regeneration
over time.
Signature lifetime jitter also, to some extent, benefits valida-
tors and servers by spreading out cache expiration, i.e., if
large numbers of RRSIGs do not expire at the same time from all
caches, there is less congestion than if all validators need to
refetch at around the same time.
-L serial
When writing a signed zone to "raw" format, this option sets the
"source serial" value in the header to the specified serial num-
ber. (This is expected to be used primarily for testing pur-
poses.)
-n ncpus
This option specifies the number of threads to use. By default,
one thread is started for each detected CPU.
-N soa-serial-format
This option sets the SOA serial number format of the signed zone.
Possible formats are keep (the default), increment, unixtime, and
date.
keep This format indicates that the SOA serial number should
not be modified.
increment
This format increments the SOA serial number using RFC
1982 <https://datatracker.ietf.org/doc/html/rfc1982.html>
arithmetic.
unixtime
This format sets the SOA serial number to the number of
seconds since the beginning of the Unix epoch, unless the
serial number is already greater than or equal to that
value, in which case it is simply incremented by one.
date This format sets the SOA serial number to today's date, in
YYYYMMDDNN format, unless the serial number is already
greater than or equal to that value, in which case it is
simply incremented by one.
-o origin
This option sets the zone origin. If not specified, the name of
the zone file is assumed to be the origin.
-O output-format
This option sets the format of the output file containing the
signed zone. Possible formats are text (the default), which is
the standard textual representation of the zone; full, which is
text output in a format suitable for processing by external
scripts; and raw and raw=N, which store the zone in binary for-
mats for rapid loading by named <#std-iscman-named>. raw=N speci-
fies the format version of the raw zone file: if N is 0, the raw
file can be read by any version of named <#std-iscman-named>; if
N is 1, the file can be read by release 9.9.0 or higher. The de-
fault is 1.
-P This option disables post-sign verification tests.
The post-sign verification tests ensure that for each algorithm
in use there is at least one non-revoked self-signed KSK key,
that all revoked KSK keys are self-signed, and that all records
in the zone are signed by the algorithm. This option skips these
tests.
-Q This option removes signatures from keys that are no longer ac-
tive.
Normally, when a previously signed zone is passed as input to the
signer, and a DNSKEY record has been removed and replaced with a
new one, signatures from the old key that are still within their
validity period are retained. This allows the zone to continue to
validate with cached copies of the old DNSKEY RRset. The -Q op-
tion forces dnssec-signzone to remove signatures from keys that
are no longer active. This enables ZSK rollover using the proce-
dure described in RFC 6781 Section 4.1.1.1 <https://datatracker
.ietf.org/doc/html/rfc6781.html#section-4.1.1.1> ("Pre-Publish
Zone Signing Key Rollover").
-q This option enables quiet mode, which suppresses unnecessary out-
put. Without this option, when dnssec-signzone is run it prints
three pieces of information to standard output: the number of
keys in use; the algorithms used to verify the zone was signed
correctly and other status information; and the filename contain-
ing the signed zone. With the option that output is suppressed,
leaving only the filename.
-R This option removes signatures from keys that are no longer pub-
lished.
This option is similar to -Q, except it forces dnssec-signzone to
remove signatures from keys that are no longer published. This
enables ZSK rollover using the procedure described in RFC 6781
Section 4.1.1.2 <https://datatracker.ietf.org/doc/html/rfc6781
.html#section-4.1.1.2> ("Double Signature Zone Signing Key
Rollover").
-S This option enables smart signing, which instructs dnssec-sign-
zone to search the key repository for keys that match the zone
being signed, and to include them in the zone if appropriate.
When a key is found, its timing metadata is examined to determine
how it should be used, according to the following rules. Each
successive rule takes priority over the prior ones:
If no timing metadata has been set for the key, the key is
published in the zone and used to sign the zone.
If the key's publication date is set and is in the past, the
key is published in the zone.
If the key's activation date is set and is in the past, the
key is published (regardless of publication date) and used to
sign the zone.
If the key's revocation date is set and is in the past, and
the key is published, then the key is revoked, and the revoked
key is used to sign the zone.
If either the key's unpublication or deletion date is set and
in the past, the key is NOT published or used to sign the
zone, regardless of any other metadata.
If the key's sync publication date is set and is in the past,
synchronization records (type CDS and/or CDNSKEY) are created.
If the key's sync deletion date is set and is in the past,
synchronization records (type CDS and/or CDNSKEY) are removed.
-T ttl This option specifies a TTL to be used for new DNSKEY records im-
ported into the zone from the key repository. If not specified,
the default is the TTL value from the zone's SOA record. This op-
tion is ignored when signing without -S, since DNSKEY records are
not imported from the key repository in that case. It is also ig-
nored if there are any pre-existing DNSKEY records at the zone
apex, in which case new records' TTL values are set to match
them, or if any of the imported DNSKEY records had a default TTL
value. In the event of a conflict between TTL values in imported
keys, the shortest one is used.
-t This option prints statistics at completion.
-u This option updates the NSEC/NSEC3 chain when re-signing a previ-
ously signed zone. With this option, a zone signed with NSEC can
be switched to NSEC3, or a zone signed with NSEC3 can be switched
to NSEC or to NSEC3 with different parameters. Without this op-
tion, dnssec-signzone retains the existing chain when re-signing.
-v level
This option sets the debugging level.
-x This option indicates that BIND 9 should only sign the DNSKEY,
CDNSKEY, and CDS RRsets with key-signing keys, and should omit
signatures from zone-signing keys.
-z This option indicates that BIND 9 should ignore the KSK flag on
keys when determining what to sign. This causes KSK-flagged keys
to sign all records, not just the DNSKEY RRset.
-3 salt
This option generates an NSEC3 chain with the given hex-encoded
salt. A dash (-) can be used to indicate that no salt is to be
used when generating the NSEC3 chain.
Note:
-3 - is the recommended configuration. Adding salt provides no
practical benefits. See RFC 9276 <https://datatracker.ietf
.org/doc/html/rfc9276.html>.
-H iterations
This option indicates that, when generating an NSEC3 chain, BIND
9 should use this many iterations. The default is 0.
Warning:
Values greater than 0 cause interoperability issues and also
increase the risk of CPU-exhausting DoS attacks. See RFC 9276
<https://datatracker.ietf.org/doc/html/rfc9276.html>.
-A This option indicates that, when generating an NSEC3 chain, BIND
9 should set the OPTOUT flag on all NSEC3 records and should not
generate NSEC3 records for insecure delegations.
Warning:
Do not use this option unless all its implications are fully
understood. This option is intended only for extremely large
zones (comparable to com.) with sparse secure delegations.
See RFC 9276 <https://datatracker.ietf.org/doc/html/rfc9276
.html>.
-AA This option turns the OPTOUT flag off for all records. This is
useful when using the -u option to modify an NSEC3 chain which
previously had OPTOUT set.
zonefile
This option sets the file containing the zone to be signed.
key This option specifies which keys should be used to sign the zone.
If no keys are specified, the zone is examined for DNSKEY records
at the zone apex. If these records are found and there are match-
ing private keys in the current directory, they are used for
signing.
EXAMPLE
The following command signs the example.com zone with the ECD-
SAP256SHA256 key generated by dnssec-keygen <#std-iscman-dnssec-keygen>
(Kexample.com.+013+17247). Because the -S option is not being used, the
zone's keys must be in the master file (db.example.com). This invocation
looks for dsset files in the current directory, so that DS records can
be imported from them (-g).
% dnssec-signzone -g -o example.com db.example.com \
Kexample.com.+013+17247
db.example.com.signed
%
In the above example, dnssec-signzone creates the file db.exam-
ple.com.signed. This file should be referenced in a zone statement in
the named.conf <#std-iscman-named.conf> file.
This example re-signs a previously signed zone with default parameters.
The private keys are assumed to be in the current directory.
% cp db.example.com.signed db.example.com
% dnssec-signzone -o example.com db.example.com
db.example.com.signed
%
SEE ALSO
dnssec-keygen(8) <#std-iscman-dnssec-keygen>, BIND 9 Administrator Ref-
erence Manual, RFC 4033 <https://datatracker.ietf.org/doc/html/rfc4033
.html>, RFC 6781 <https://datatracker.ietf.org/doc/html/rfc6781.html>.
Author
Internet Systems Consortium
Copyright
2026, Internet Systems Consortium
9.20.21-1~deb13u1-Debian 2026-03-13 DNSSEC-SIGNZONE(1)
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