rndc — name server control utility
rndc  [-b ] [source-address-c ] [config-file-k ] [key-file-s ] [server-p ] [port-V] [-y ] {command}key_id
rndc controls the operation of a name server. It supersedes the ndc utility that was provided in old BIND releases. If rndc is invoked with no command line options or arguments, it prints a short summary of the supported commands and the available options and their arguments.
rndc communicates with the name server over a TCP connection, sending commands authenticated with digital signatures. In the current versions of rndc and named, the only supported authentication algorithm is HMAC-MD5, which uses a shared secret on each end of the connection. This provides TSIG-style authentication for the command request and the name server's response. All commands sent over the channel must be signed by a key_id known to the server.
rndc reads a configuration file to determine how to contact the name server and decide what algorithm and key it should use.
source-address
            Use source-address
            as the source address for the connection to the server.
            Multiple instances are permitted to allow setting of both
            the IPv4 and IPv6 source addresses.
          
config-file
            Use config-file
            as the configuration file instead of the default,
            /etc/rndc.conf.
          
key-file
            Use key-file
            as the key file instead of the default,
            /etc/rndc.key.  The key in
            /etc/rndc.key will be used to
            authenticate
            commands sent to the server if the config-file
            does not exist.
          
serverserver is
            the name or address of the server which matches a
            server statement in the configuration file for
            rndc.  If no server is supplied on the
            command line, the host named by the default-server clause
            in the options statement of the rndc
	    configuration file will be used.
          
port
            Send commands to TCP port
            port
            instead
            of BIND 9's default control channel port, 953.
          
Enable verbose logging.
key_id
            Use the key key_id
            from the configuration file.
            key_id
            must be
            known by named with the same algorithm and secret string
            in order for control message validation to succeed.
            If no key_id
            is specified, rndc will first look
            for a key clause in the server statement of the server
            being used, or if no server statement is present for that
            host, then the default-key clause of the options statement.
            Note that the configuration file contains shared secrets
            which are used to send authenticated control commands
            to name servers.  It should therefore not have general read
            or write access.
          
For the complete set of commands supported by rndc, see the BIND 9 Administrator Reference Manual or run rndc without arguments to see its help message.
rndc does not yet support all the commands of the BIND 8 ndc utility.
      There is currently no way to provide the shared secret for a
      key_id without using the configuration file.
    
Several error messages could be clearer.