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man pages section 1M: System Administration Commands

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Updated: July 2017



rndc-confgen - rndc key generation tool


rndc-confgen [-ah] [-b keysize] [-c keyfile] [-k keyname] 
     [-p port] [-r randomfile] [-s address] [-t chrootdir] 
     [-u user]


The rndc-confgen utility generates configuration files for rndc(1M). This utility can be used as a convenient alternative to writing by hand the rndc.conf(4) file and the corresponding controls and key statements in named.conf. It can also be run with the –a option to set up a rndc.key file and avoid altogether the need for a rndc.conf file and a controls statement.


The following options are supported:


Perform automatic rndc configuration. This option creates a file rndc.key in /etc (or however sysconfdir was specified when BIND was built) that is read by both rndc and named(1M) on startup. The rndc.key file defines a default command channel and authentication key allowing rndc to communicate with named with no further configuration.

Running rndc-confgen with –a specified allows BIND 9 and rndc to be used as drop-in replacements for BIND 8 and ndc, with no changes to the existing BIND 8 named.conf file.

If a more elaborate configuration than that generated by rndc-confgen –a is required, for example if rndc is to be used remotely, you should run rndc-confgen without the –a option and set up rndc.conf and named.conf files, as directed.

–b keysize

Specify the size of the authentication key in bits. The keysize argument must be between 1 and 512 bits; the default is 128.

–c keyfile

Used with the –a option to specify an alternate location for rndc.key.


Print a short summary of the options and arguments to rndc-confgen.

–k keyname

Specify the key name of the rndc authentication key. The keyname argument must be a valid domain name. The default is rndc-key.

–p port

Specify the command channel port where named listens for connections from rndc. The default is 953.

–r randomfile

Specify a source of random data for generating the authorization. By default, /dev/random is used. The randomdev argument specifies the name of a character device or file containing random data to be used instead of the default. The special value keyboard indicates that keyboard input should be used.

–s address

Specify the IP address where named listens for command channel connections from rndc. The default is the loopback address

–t chrootdir

Used with the –a option to specify a directory where named will run after the root directory is changed with chroot(2). An additional copy of the rndc.key will be written relative to this directory so that it will be found by the named in the new directory.

–u user

Used with the –a option to set the owner of the rndc.key file generated. If –t is also specified only the file in the chroot area has its owner changed.


Example 1 Create Automatic rndc Configuration

The following command creates an automatic rndc configuration, so that rndc can be used immediately.

# rndc-confgen -a
Example 2 Print a Sample rndc.conf File

The following command prints a sample rndc.conf file with corresponding controls and key statements. These statements can subsequently be manually inserted in the file named.conf.

# rndc-confgen


See attributes(5) for descriptions of the following attributes:

Interface Stability

See Also

chroot(2), named(1M), rndc(1M), rndc.conf(4), attributes(5)

See the BIND 9 Administrator's Reference Manual. As of the date of publication of this man page, this document is available at https://kb.isc.org/article/AA-01031https://kb.isc.org/article/AA-01031.