<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">/* -*- Mode: Text -*- */

autogen definitions options;

#include copyright.def
#include version.def

// We want the synopsis to be "/etc/ntp.keys" but we need the prog-name
// to be ntp.keys - the latter is also how autogen produces the output
// file name.
prog-name	= "ntp.keys";
file-path	= "/etc/ntp.keys";
prog-title	= "NTP symmetric key file format";

/* explain: Additional information whenever the usage routine is invoked */
explain = &lt;&lt;- _END_EXPLAIN
	_END_EXPLAIN;

doc-section	= {
  ds-type	= 'DESCRIPTION';
  ds-format	= 'mdoc';
  ds-text	= &lt;&lt;- _END_PROG_MDOC_DESCRIP
This document describes the format of an NTP symmetric key file.
For a description of the use of this type of file, see the
.Qq Authentication Support
section of the
.Xr ntp.conf 5
page.
.Pp
.Xr ntpd 8
reads its keys from a file specified using the
.Fl k
command line option or the
.Ic keys
statement in the configuration file.
While key number 0 is fixed by the NTP standard
(as 56 zero bits)
and may not be changed,
one or more keys numbered between 1 and 65535
may be arbitrarily set in the keys file.
.Pp
The key file uses the same comment conventions
as the configuration file.
Key entries use a fixed format of the form
.Pp
.D1 Ar keyno type key opt_IP_list
.Pp
where
.Ar keyno
is a positive integer (between 1 and 65535),
.Ar type
is the message digest algorithm,
.Ar key
is the key itself, and
.Ar opt_IP_list
is an optional comma-separated list of IPs
where the
.Ar keyno
should be trusted.
that are allowed to serve time.
Each IP in
.Ar opt_IP_list
may contain an optional
.Cm /subnetbits
specification which identifies the number of bits for
the desired subnet of trust.
If
.Ar opt_IP_list
is empty,
any properly-authenticated message will be
accepted.
.Pp
The
.Ar key
may be given in a format
controlled by the
.Ar type
field.
The
.Ar type
.Li MD5
is always supported.
If
.Li ntpd
was built with the OpenSSL library
then any digest library supported by that library may be specified.
However, if compliance with FIPS 140-2 is required the
.Ar type
must be either
.Li SHA
or
.Li SHA1 .
.Pp
What follows are some key types, and corresponding formats:
.Pp
.Bl -tag -width RMD160 -compact
.It Li MD5
The key is 1 to 16 printable characters terminated by
an EOL,
whitespace,
or
a
.Li #
(which is the "start of comment" character).
.Pp
.It Li SHA
.It Li SHA1
.It Li RMD160
The key is a hex-encoded ASCII string of 40 characters,
which is truncated as necessary.
.El
.Pp
Note that the keys used by the
.Xr ntpq 8
and
.Xr ntpdc 8
programs are checked against passwords
requested by the programs and entered by hand,
so it is generally appropriate to specify these keys in ASCII format.
	_END_PROG_MDOC_DESCRIP;
};

doc-section	= {
  ds-type	= 'FILES';
  ds-format	= 'mdoc';
  ds-text	= &lt;&lt;- _END_MDOC_FILES
.Bl -tag -width /etc/ntp.keys -compact
.It Pa /etc/ntp.keys
the default name of the configuration file
.El
	_END_MDOC_FILES;
};

doc-section	= {
  ds-type	= 'SEE ALSO';
  ds-format	= 'mdoc';
  ds-text	= &lt;&lt;- _END_MDOC_SEE_ALSO
.Xr ntp.conf 5 ,
.Xr ntpd 1ntpdmdoc ,
.Xr ntpdate 1ntpdatemdoc ,
.Xr ntpdc 1ntpdcmdoc ,
.Xr sntp 1sntpmdoc
	_END_MDOC_SEE_ALSO;
};

/*
doc-section	= {
  ds-type	= 'BUGS';
  ds-format	= 'mdoc';
  ds-text	= &lt;&lt;- _END_MDOC_BUGS
.Xr ntpd 8
has gotten rather fat.
While not huge, it has gotten larger than might
be desirable for an elevated-priority daemon running on a workstation,
particularly since many of the fancy features which consume the space
were designed more with a busy primary server, rather than a high
stratum workstation, in mind.
	_END_MDOC_BUGS;
};
*/

doc-section	= {
  ds-type	= 'NOTES';
  ds-format	= 'mdoc';
  ds-text	= &lt;&lt;- _END_MDOC_NOTES
This document was derived from FreeBSD.
	_END_MDOC_NOTES;
};
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