bind9/bin/rndc/rndc.conf.5

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.\" $Id: rndc.conf.5,v 1.6 2000/08/01 01:18:48 tale Exp $
.\"
.Dd Jun 30, 2000
.Dt RDNC.CONF 5
.Os BIND9 9
.ds vT BIND9 Programmer's Manual
.Sh NAME
.Nm rdnc.conf
.Nd rdnc configuration file
.Sh SYNOPSIS
.Nm rdnc.conf
.Sh DESCRIPTION
The BIND9 utility for controlling the name server,
.Nm rndc ,
has its own configuration file
.Pa /etc/rndc.conf .
This file has a similar structure and syntax to
.Pa named.conf ,
the file used to configure the name server.
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:
.Bl -tag -width UNIX-style:
.It C style: /* */
.It C++ style: // to end of line
.It Unix style: # to end of line
.El
.Pp
.Pa rndc.conf
is much simpler than
.Pa named.conf .
The file uses three statements: an
.Dv options{}
statement, a
.Dv server{}
statement and a
.Dv key{}
statement.
.Pp
The
.Dv options{}
statement contains two clauses.
The
.Dv default-server
clause
is followed by the name or address of a name server.
This host will
be used when no name server is given as an argument to
.Nm rndc .
The
.Dv default-key
clause
is followed by the name of a key which is identified by a
.Dv key{}
statement.
If no
.Fl y
option is provided on the
.Xr rndc
command line, and no
.Dv key
clause is found in a a matching
.Dv server{}
statement, this default key will be used to authenticate the server's
commands and responses.
.Pp
After the keyword
.Dv server ,
the
.Dv server{}
statement is followed by a string which is the hostname or address for a
name server.
The statement has a single clause,
.Dv key .
The key name must match the name of a
.Dv key{}
statement in the file.
.Pp
The
.Dv key{}
statement begins with an identifying string, the name of the key.
The statement has two clauses.
.Dv algorithm
identifies the encryption algorithm for
.Nm rndc
to use; currently only HMAC-MD5 is supported.
This is followed by a
.Dv secret
clause which contains the base-64 encoding of the
algorithm's encryption key.
The base-64 string is enclosed in double quotes.
.Pp
There are two common ways to generate the base-64 string for the
.Dv secret .
The BIND 9 program
.Xr dnssec-keygen 8
can be used to generate a random key, or the
.Xr mmencode 1
program, also known as
.Xr mimencode 1 ,
can be used to generate a base-64 string from known input.
.Xr mmencode
does not ship with BIND 9 but is available on many systems.
See the
.Sx EXAMPLES
section for sample command lines for each.
.Pp
Host and key names must be quoted using double quotes if they
match a keyword, such as having a key named "key".
.Sh EXAMPLE
.Bd -literal indent
options {
    default-server  localhost;
    default-key     samplekey;
};

server localhost {
    key     samplekey;
};

key samplekey {
    algorithm hmac-md5;
    secret "c3Ryb25nIGVub3VnaCBmb3IgYSBtYW4gYnV0IG1hZGUgZm9yIGEgd29tYW4K";
};
.Ed
.Pp
In the above example,
.Nm rndc
will by default use the server at localhost (127.0.0.1) and the key called
.Dv samplekey .
Commands to the localhost server will use the
.Dv samplekey
key.
The
.Dv key{}
statement indicates that
.Dv samplekey
uses the HMAC-MD5 algorithm and its
.Dv secret
clause contains the base-64 encoding of the HMAC-MD5 secret enclosed
in double quotes.
.Pp
To generate a random secret with
.Xr dnssec-keygen :
.Bd -literal indent
$ dnssec-keygen -a hmac-md5 -b 128 -n user rndc
.Ed
.Pp
The base-64 string will appear in two files,
.Pa Krndc.+157.+{random}.key
and
.Pa Krndc.+157.+{random}.private .
After extracting the key to be
placed in the
.Nm rndc.conf
and
.Xr named.conf
.Dv key{}
statements, the
.Pa .key
and
.Pa .private
files can be removed.
.Pp
To generate a secret from known input with
.Xr mmenode :
.Bd -literal indent
$ echo "known plaintext for a secret" | mmencode
.Ed
.Sh LIMITATIONS
There is currently no way to specify the port for
.Xr rndc
to use.  This will be remedied in future releases by allowing a
.Dv port
clause to the
.Dv server{}
statement and a
.Dv default-port
clause to the
.Dv options{}
statement.
.Sh SEE ALSO
.Xr rndc 8 ,
.Xr named.conf 8 ,
.Xr dnssec-keygen 8 ,
.Xr mmencode 1 ,
"BIND9 Administrators Manual".