DDNS-CONFGEN(8)

NAME
ddns-confgen - ddns key generation tool

SYNOPSIS

ddns-confgen [-a algorithm] [-h] [-k keyname] [-q] [-s name] [-z zone]

DESCRIPTION

ddns-confgen is an utility that generates keys for use in TSIG signing. The resulting keys can be used, for example, to secure dynamic DNS updates to a zone, or for the rndc command channel.

The key name can specified using -k parameter and defaults to ddns-key. The generated key is accompanied by configuration text and instructions that can be used with nsupdate and named when setting up dynamic DNS, including an example update-policy statement. (This usage is similar to the rndc-confgen command for setting up command-channel security.)

Note that named itself can configure a local DDNS key for use with nsupdate -l; it does this when a zone is configured with update-policy local;. ddns-confgen is only needed when a more elaborate configuration is required: for instance, if nsupdate is to be used from a remote system.

OPTIONS

-a algorithm
    This option specifies the algorithm to use for the TSIG key. Available choices are: hmac-md5, hmac-sha1, hmac-sha224, hmac-sha256, hmac-sha384, and hmac-sha512. The default is hmac-sha256. Options are case-insensitive, and the "hmac-" prefix may be omitted.

-h  This option prints a short summary of options and arguments.

-k keyname
    This option specifies the key name of the DDNS authentication key. The default is ddns-key when neither the -s nor -z option is specified; otherwise, the default is ddns-key as a separate label followed by the argument of the option, e.g., ddns-key.example.com. The key name must have the format of a valid domain name, consisting of letters, digits, hyphens, and periods.

-q  This option enables quiet mode, which prints only the key, with no explanatory text or usage examples. This is essentially identical to tsig-keygen.

-s name
    This option generates a configuration example to allow dynamic updates of a single hostname. The example named.conf text shows how to set an update policy for the specified name using the "name" nametype. The default key name is ddns-key.name. Note that the "self" nametype cannot be used, since the name to be updated may differ from the key name. This option cannot be used with the -z option.

-z zone
    This option generates a configuration example to allow dynamic updates of a zone. The example named.conf text shows how to set an update policy for the specified zone using the "zonesub" nametype, allowing updates to all subdomain names within that zone. This option cannot be used with the -s option.

SEE ALSO

nsupdate(1), named.conf(5), named(8), BIND 9 Administrator Reference Manual.

AUTHOR
Internet Systems Consortium

COPYRIGHT
2026, Internet Systems Consortium