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RNDC.CONF(5)                        BIND 9                        RNDC.CONF(5)

       rndc.conf - rndc configuration file


       rndc.conf is the configuration file for rndc, the BIND 9 name server
       control utility. This file has a similar structure and syntax to
       named.conf. Statements are enclosed in braces and terminated with a
       semi-colon. Clauses in the statements are also semi-colon terminated.
       The usual comment styles are supported:

       C style: /* */

       C++ style: // to end of line

       Unix style: # to end of line

       rndc.conf is much simpler than named.conf. The file uses three
       statements: an options statement, a server statement, and a key

       The options statement contains five clauses. The default-server clause
       is followed by the name or address of a name server. This host is used
       when no name server is given as an argument to rndc.  The default-key
       clause is followed by the name of a key, which is identified by a key
       statement. If no keyid is provided on the rndc command line, and no key
       clause is found in a matching server statement, this default key is
       used to authenticate the server's commands and responses. The
       default-port clause is followed by the port to connect to on the remote
       name server. If no port option is provided on the rndc command line,
       and no port clause is found in a matching server statement, this
       default port is used to connect. The default-source-address and
       default-source-address-v6 clauses can be used to set the IPv4 and IPv6
       source addresses respectively.

       After the server keyword, the server statement includes a string which
       is the hostname or address for a name server. The statement has three
       possible clauses: key, port, and addresses. The key name must match the
       name of a key statement in the file. The port number specifies the port
       to connect to. If an addresses clause is supplied, these addresses are
       used instead of the server name. Each address can take an optional
       port. If an source-address or source-address-v6 is supplied, it is used
       to specify the IPv4 and IPv6 source address, respectively.

       The key statement begins with an identifying string, the name of the
       key. The statement has two clauses. algorithm identifies the
       authentication algorithm for rndc to use; currently only HMAC-MD5 (for
       compatibility), HMAC-SHA1, HMAC-SHA224, HMAC-SHA256 (default),
       HMAC-SHA384, and HMAC-SHA512 are supported. This is followed by a
       secret clause which contains the base-64 encoding of the algorithm's
       authentication key. The base-64 string is enclosed in double quotes.

       There are two common ways to generate the base-64 string for the
       secret.  The BIND 9 program rndc-confgen can be used to generate a
       random key, or the mmencode program, also known as mimencode, can be
       used to generate a base-64 string from known input. mmencode does not
       ship with BIND 9 but is available on many systems. See the Example
       section for sample command lines for each.


          options {
            default-server  localhost;
            default-key     samplekey;

          server localhost {
            key             samplekey;

          server testserver {
            key     testkey;
            addresses   { localhost port 5353; };

          key samplekey {
            algorithm       hmac-sha256;
            secret          "6FMfj43Osz4lyb24OIe2iGEz9lf1llJO+lz";

          key testkey {
            algorithm   hmac-sha256;
            secret      "R3HI8P6BKw9ZwXwN3VZKuQ==";

       In the above example, rndc by default uses the server at localhost
       ( and the key called "samplekey". Commands to the localhost
       server use the "samplekey" key, which must also be defined in the
       server's configuration file with the same name and secret. The key
       statement indicates that "samplekey" uses the HMAC-SHA256 algorithm and
       its secret clause contains the base-64 encoding of the HMAC-SHA256
       secret enclosed in double quotes.

       If rndc -s testserver is used, then rndc connects to the server on
       localhost port 5353 using the key "testkey".

       To generate a random secret with rndc-confgen:


       A complete rndc.conf file, including the randomly generated key, is
       written to the standard output. Commented-out key and controls
       statements for named.conf are also printed.

       To generate a base-64 secret with mmencode:

       echo "known plaintext for a secret" | mmencode

       The name server must be configured to accept rndc connections and to
       recognize the key specified in the rndc.conf file, using the controls
       statement in named.conf. See the sections on the controls statement in
       the BIND 9 Administrator Reference Manual for details.

       rndc(8), rndc-confgen(8), mmencode(1), BIND 9 Administrator Reference

       Internet Systems Consortium

       2022, Internet Systems Consortium

9.16.33                                                           RNDC.CONF(5)