Provided by: bind9-utils_9.18.30-0ubuntu0.20.04.2_amd64 
NAME
dnssec-signzone - DNSSEC zone signing tool
SYNOPSIS
dnssec-signzone [-a] [-c class] [-d directory] [-D] [-E engine] [-e end-time] [-f output-file] [-g] [-h]
[-i interval] [-I input-format] [-j jitter] [-K directory] [-k key] [-L serial] [-M maxttl] [-N
soa-serial-format] [-o origin] [-O output-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 iterations] [-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 delegations 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 resulting file can be included in the original
zone file with $INCLUDE. This option cannot be combined with -O raw or serial-number updating.
-E engine
This option specifies the hardware to use for cryptographic operations, such as a secure key store
used for signing, when applicable.
When BIND 9 is built with OpenSSL, this needs to be set to the OpenSSL engine identifier that
drives the cryptographic accelerator or hardware service module (usually pkcs11).
-g This option indicates that DS records for child zones should be generated from a dsset- or keyset-
file. Existing DS records are removed.
-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 specified 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.
(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
YYYYMMDDHHMMSS 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
default. 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.) extended
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 filename. 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 between 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.
-I input-format
This option sets the format of the input zone file. Possible formats 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 validators 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 number. (This is expected to be used primarily for testing
purposes.)
-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 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 formats for rapid loading by named. raw=N specifies the format version of the raw
zone file: if N is 0, the raw file can be read by any version of named; if N is 1, the file can be
read by release 9.9.0 or higher. The default 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 active.
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 option forces dnssec-signzone to remove signatures from keys that are
no longer active. This enables ZSK rollover using the procedure described in RFC 6781#4.1.1.1
("Pre-Publish Key Rollover").
-q This option enables quiet mode, which suppresses unnecessary output. 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 containing 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 published.
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#4.1.1.2 ("Double Signature Zone Signing Key Rollover").
-S This option enables smart signing, which instructs dnssec-signzone 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 imported into the zone from the key
repository. If not specified, the default is the TTL value from the zone's SOA record. This option
is ignored when signing without -S, since DNSKEY records are not imported from the key repository
in that case. It is also ignored 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 previously 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 option, 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. (This is similar to the
dnssec-dnskey-kskonly yes; zone option in named.)
-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. (This is
similar to the update-check-ksk no; zone option in named.)
-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.
-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.
-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.
-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
matching private keys in the current directory, they are used for signing.
EXAMPLE
The following command signs the example.com zone with the ECDSAP256SHA256 key generated by 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.example.com.signed. This file should be
referenced in a zone statement in the 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), BIND 9 Administrator Reference Manual, RFC 4033, RFC 6781.
AUTHOR
Internet Systems Consortium
COPYRIGHT
2025, Internet Systems Consortium