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 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.
Use config-file as the configuration file instead of the default, /etc/rndc.conf.
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.
server 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 option statement of the configuration file will be used.
Send commands to TCP port port instead of BIND 9's default control channel port, 953.
Enable verbose logging.
Use the key keyid from the configuration file. keyid must be known by named with the same algorithm and secret string in order for control message validation to succeed. If no keyid 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.