dnssec-signzone - DNSSEC zone signing tool
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...]
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.
- -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, -O map, 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). When BIND is built with
native PKCS#11 cryptography (--enable-native-pkcs11), it defaults
to the path of the PKCS#11 provider library specified via
--with-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), raw, and map. 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" or "map" 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 map,
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 4641#4.2.1.1 ("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 4641#4.2.1.2 ("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.
- -H iterations
- This option indicates that, when generating an NSEC3 chain, BIND 9 should
use this many iterations. The default is 10.
WARNING:
Values greater than 0 cause interoperability issues and
also increase the risk of CPU-exhausting DoS attacks. The default value has
not been changed because the best practices has changed only after BIND 9.16
reached Extended Support Version status.
- -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.
Using this option twice (i.e., -AA) 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.
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
%
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