dnssec-signzone Command

Purpose

Domain name system security extensions (DNSSEC) zone signing tool.

Syntax

dnssec-signzone [-3 salt] [-A] [-a] [-c class] [-d directory] [-D][-E engine] [-e end-time] [-f output-file] [-g] [-H iterations] [-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 start-time] [-T ttl] [-t] [-u] [-V] [-v level] [-X extended end-time] [-x] [-z] zonefile [key...]

Description

The dnssec-signzone command signs a zone. It generates NSEC and RRSIG records and produces a signed version of the zone. The presence or absence of a key set file for each child zone determines the security status of delegations from the signed zone (that is, whether the child zones are secure or not).

Flags

Item	Description
-3 `salt`	Generates an NSEC3 chain with the specified hex-encoded salt. A dash (-) can be used to indicate that no salt must be used when generating the NSEC3 chain. The `salt` parameter can be random data that hashes data, a password, or passphrase. Salts are used to safeguard passwords.
-A	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. Using this option twice (that is, -AA) turns off the `OPTOUT` flag for all records. This is useful when using the -u option to modify an NSEC3 chain on which the `OPTOUT` flag was set.
-a	Verifies all generated signatures.
-C	Sets compatibility mode, in which a keyset-zonename file is generated in addition to dsset-zonename file when signing a zone. These files are used by older versions of the dnssec-signzone command.
-c `class`	Specifies the DNS class of the zone.
-D	Indicates that only record types that are automatically managed by the dnssec-signzone command, that is, 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 update operations.
-d `directory`	Looks for key set files in the directory that is specified by the `directory` argument.
-E `engine`	Specifies the hardware to use for cryptographic operations, such as a secure key store that is used for signing, when applicable. When BIND 9 is built with OpenSSL, this flag 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`.
-e `end-time`	Specifies the date and time when the generated RRSIG records expire. As with the `start-time` argument, 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 you do not specify the `end-time` argument, the command uses 30 days from the start time as a default.
-f `output-file`	Specifies the name of the output file that contains the signed zone. The default is to append `.signed` to the input file name.
-g	Generates DS records for child zones from key set files. This flag removes existing DS records.
-h	Prints a short summary of the options and arguments of the dnssec-signzone command.
-H `iterations`	Indicates that, when generating an NSEC3 chain, BIND 9 must use the specified number of iterations. The default value is 10.
-I `input-format`	Specifies the format of the input zone file. Possible formats are text (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.
-i `interval`	When a previously signed zone is passed as input, records might be resigned. The interval option specifies the cycle interval as an offset from the current time (in seconds). If an RRSIG record expires after the cycle interval, it is retained. Otherwise, it is considered to be expiring soon, and it is then replaced. The default cycle interval is one quarter of the difference between the signature end and start times. If you specify neither the `end-time` argument or the `start-time` argument, the dnssec-signzone command 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.
-j `jitter`	When you sign a zone with a fixed signature lifetime, all RRSIG records issued at the time of signing expire simultaneously. If the zone is incrementally signed, for example, a previously signed zone is passed as input to the signer and all expired signatures must be regenerated at about the same time. The `jitter` argument specifies a jitter window that is used to randomize the signature expire time, thus spreading incremental signature regeneration over time. Signature lifetime jitter can also benefit validators and servers by spreading out cache expiration. For example, if large numbers of RRSIGs do not expire at the same time from all caches, there is less congestion than if all validators must refetch at mostly the same time.
-K `directory`	Specifies the directory to search for DNSSEC keys. If not specified, it defaults to the current directory.
-k `key`	Treats the specified key as a key-signing key ignoring any key flags. You can specify this option multiple times.
-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 flag is expected to be used primarily for testing purposes).
-M `maxttl`	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, which are 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.
-N `soa-serial-format`	Specifies the SOA serial number format of the signed zone. The `soa-serial-format` argument can be one of the following values: keep Does not modify the SOA serial number. It is the default value. increment Increases the SOA serial number by using RFC 1982 arithmetic. unixtime Sets the SOA serial number to the number of seconds since epoch. date 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.
-n `ncpus`	Specifies the number of threads to use. By default, the command starts one thread for each detected processor.
-O `output-format`	Specifies the format of the output file that contains 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 command. `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 command; if N is `1`, the file can be read by release 9.9.0, or later. The default value is `1`.
-o `origin`	Specifies the zone origin. If not specified, the name of the zone file is assumed to be the origin.
-P	Disables post-sign verification tests. The post-sign verification tests ensure that at least one non-revoked self-signed KSK key exist for each algorithm, 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	Removes signatures from keys that are no longer active. Typically, when a previously signed zone is passed as input to the signer, and a DNSKEY record has been removed and replaced with a new record, 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 command 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	Enables quiet mode, which suppresses unnecessary output. Without this option, when dnssec-signzone command is run, it prints the following information to standard output: the number of keys in use; the algorithms used to verify whether the zone was signed correctly and other status information; and the filename containing the signed zone. If you use this option, the output is suppressed and only the filename is retained.
-R	Removes signatures from keys that are no longer published. This option is similar to -Q, except that it forces dnssec-signzone command 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	Enables smart signing, which instructs dnssec-signzone command 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 rules: If no timing metadata has been set for the key, the key is published in the zone and is 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.
-s `start-time`	Specifies the date and time when the generated RRSIG records become valid. It 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 you do not specify the `start-time` argument, the command uses the current time minus 1 hour (to allow for clock skew).
-T `ttl`	Specifies a TTL to be used for new DNSKEY records that are imported into the zone from the key repository. If `ttl` is not specified, the TTL value from the zone’s SOA record is used by default. 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 any pre-existing DNSKEY records exists 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 value is used.
-t	Prints statistics at completion.
-u	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 command retains the existing chain when re-signing.
-V	Prints version information.
-v `level`	Sets the debugging level.
-X `extended end-time`	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. For example, when the private component of the KSK is kept offline and the KSK signature must be refreshed manually. Similar to the `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 by default. (`end-time`, in turn, defaults to 30 days from the start time.) `extended end-time` must be later than s`tart-time`.
-x	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 `second-dnskey-kskonly yes`; zone option in named command.
-z	Ignores KSK flag on key when you determine what to sign.

Parameters

Item	Description
zonefile	The file that contains the zone to be signed.
key	The keys that are used to sign the key set. If no keys are specified, the defaults are all zone keys that have private key files in the current directory.

Examples

The following command signs the example.com zone with the ECDSAP256SHA256 key generated by dnssec-keygen command (Kexample.com.+013+17247). Because the -S option is not used, the zone’s keys must exist 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 preceding example, dnssec-signzone command 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 present in the current directory.

% cp db.example.com.signed db.example.com
% dnssec-signzone -o example.com db.example.com
db.example.com.signed
%