NAME

       dnssec-dsfromkey - DNSSEC DS RR generation tool

SYNOPSIS

       dnssec-dsfromkey [ -1 | -2 | -a alg ] [ -C ] [-T TTL] [-v level] [-K directory] {keyfile}

       dnssec-dsfromkey [ -1 | -2 | -a alg ] [ -C ] [-T TTL] [-v level] [-c class] [-A] {-f file} [dnsname]

       dnssec-dsfromkey [ -1 | -2 | -a alg ] [ -C ] [-T TTL] [-v level] [-c class] [-K directory] {-s} {dnsname}

       dnssec-dsfromkey [ -h | -V ]

DESCRIPTION

       The dnssec-dsfromkey command outputs DS (Delegation Signer) resource records (RRs), or CDS (Child DS) RRs
       with the -C option.

       By  default, only KSKs are converted (keys with flags = 257).  The -A option includes ZSKs (flags = 256).
       Revoked keys are never included.

       The input keys can be specified in a number of ways:

       By default, dnssec-dsfromkey reads a key file named in the format Knnnn.+aaa+iiiii.key, as  generated  by
       dnssec-keygen.

       With  the  -f  file  option, dnssec-dsfromkey reads keys from a zone file or partial zone file (which can
       contain just the DNSKEY records).

       With the -s option, dnssec-dsfromkey reads a keyset- file, as generated by dnssec-keygen -C.

OPTIONS

       -1     This option is an abbreviation for -a SHA1.  This digest is deprecated.

       -2     This option is an abbreviation for -a SHA-256.

       -a algorithm
              This option specifies a digest algorithm to use when converting DNSKEY records to DS records. This
              option can be repeated, so that multiple DS records are created for each DNSKEY record.

              The algorithm  must  be  one  of  SHA-1  (deprecated),  SHA-256,  or  SHA-384.  These  values  are
              case-insensitive,  and  the  hyphen  may  be omitted. If no algorithm is specified, the default is
              SHA-256.

       -A     This option indicates that ZSKs are to be  included  when  generating  DS  records.  Without  this
              option, only keys which have the KSK flag set are converted to DS records and printed. This option
              is only useful in -f zone file mode.

       -c class
              This option specifies the DNS class; the default is IN. This option is only useful in -s keyset or
              -f zone file mode.

       -C     This option generates CDS records rather than DS records.

       -f file
              This  option  sets  zone file mode, in which the final dnsname argument of dnssec-dsfromkey is the
              DNS domain name of a zone whose master file can be read from file. If the zone name is the same as
              file, then it may be omitted.

              If file is -, then the zone data is read from the standard input. This makes it  possible  to  use
              the output of the dig command as input, as in:

              dig dnskey example.com | dnssec-dsfromkey -f - example.com

       -h     This option prints usage information.

       -K directory
              This option tells BIND 9 to look for key files or keyset- files in directory.

       -s     This  option enables keyset mode, in which the final dnsname argument from dnssec-dsfromkey is the
              DNS domain name used to locate a keyset- file.

       -T TTL This option specifies the TTL of the DS records. By default the TTL is omitted.

       -v level
              This option sets the debugging level.

       -V     This option prints version information.

EXAMPLE

       To build the SHA-256 DS RR from the Kexample.com.+003+26160 keyfile, issue the following command:

       dnssec-dsfromkey -2 Kexample.com.+003+26160

       The command returns something similar to:

       example.com. IN DS 26160 5 2 3A1EADA7A74B8D0BA86726B0C227AA85AB8BBD2B2004F41A868A54F0C5EA0B94

FILES

       The keyfile can be  designated  by  the  key  identification  Knnnn.+aaa+iiiii  or  the  full  file  name
       Knnnn.+aaa+iiiii.key, as generated by dnssec-keygen.

       The keyset file name is built from the directory, the string keyset-, and the dnsname.

CAVEAT

       A keyfile error may return "file not found," even if the file exists.

SEE ALSO

       dnssec-keygen(8),  dnssec-signzone(8), BIND 9 Administrator Reference Manual, RFC 3658 (DS RRs), RFC 4509
       (SHA-256 for DS RRs), RFC 6605 (SHA-384 for DS RRs), RFC 7344 (CDS and CDNSKEY RRs).

AUTHOR

       Internet Systems Consortium

COPYRIGHT

       2025, Internet Systems Consortium

9.18.39-0ubuntu0.24.04.1-Ubuntu                    2025-08-13                                DNSSEC-DSFROMKEY(1)