xntpd(8) - NetBSD Manual Pages

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XNTPD(8)                NetBSD System Manager's Manual                XNTPD(8)


NAME

     xntpd - Network Time Protocol (NTP) daemon


SYNOPSIS

     xntpd [-aAbdm] [-c conffile] [-f driftfile] [-k keyfile] [-l logfile] [-p
     pidfile] [-r broadcastdelay] [-s statsdir] [-t key] [-v variable] [-V
     variable]


DESCRIPTION

     xntpd is an operating system daemon which sets and maintains the system
     time-of-day in synchronism with Internet standard time servers.  xntpd is
     a complete implementation of the Network Time Protocol (NTP) version 3,
     as defined by RFC-1305, but also retains compatibility with version 1 and
     2 servers as defined by RFC-1059 and RFC-1119, respectively.  xntpd does
     all computations in 64-bit fixed point arithmetic and requires no float-
     ing point support. While the ultimate precision of this design, about 232
     picoseconds, is not achievable with ordinary workstations and networks of
     today, it may be required with future nanosecond CPU clocks and gigabit
     LANs.

     The daemon can operate in any of several modes, including symmetric ac-
     tive/passive, client/server and broadcast/multicast, as described in
     RFC-1305. A broadcast/multicast client can discover remote servers, com-
     pute server-client propagation delay correction factors and configure it-
     self automatically. This makes it possible to deploy a fleet of worksta-
     tions without specifying configuration details specific to the local en-
     vironment.

     Ordinarily, xntpd reads the ntp.conf configuration file at startup time
     in order to determine the synchronization sources and operating modes. It
     is also possible to specify a working, although limited, configuration
     entirely on the command line, obviating the need for a configuration
     file. This may be particularly appropriate when the local host is to be
     configured as a broadcast or multicast client, with all peers being de-
     termined by listening to broadcasts at run time.

     Various internal xntpd variables can be displayed and configuration op-
     tions altered while the daemon is running using the ntpq(8) and xntpdc(8)
     utility programs.

     When xntpd starts it looks at the value of umask, and if it's zero xntpd
     will set umask to 022.

     The options are as follows:

     -a      Enable authentication mode. The default is enabled, so this op-
             tion is obsolete now.

     -A      Disable authentication mode.

     -b      Synchronize using NTP broadcast messages.

     -c conffile
             Specify the name and path of the configuration file.

     -d      Specify debugging mode. This flag may occur multiple times, with
             each occurrence indicating greater detail of display.

     -f driftfile
             Specify the name and path of the drift file.

     -k keyfile
             Specify the name and path of the file containing the NTP authen-

             tication keys.

     -l logfile
             Specify the name and path of the log file. The default is the
             system log facility.

     -m      Synchronize using NTP multicast messages on the IP multicast
             group address 224.0.1.1 (requires multicast kernel).

     -p pidfile
             Specify the name and path to record the daemon's process ID.

     -r broadcastdelay
             Specify the default propagation delay from the broadcast/multi-
             cast server and this computer. This is used only if the delay
             cannot be computed automatically by the protocol.

     -s statsdir
             Specify the directory path for files created by the statistics
             facility.

     -t key  Add a key number to the trusted key list.

     -v variable
             Add a system variable.

     -V variable
             Add a system variable listed by default.


THE CONFIGURATION FILE

     The xntpd configuration file is read at initial startup in order to spec-
     ify the synchronization sources, modes and other related information.
     Usually, it is installed in the /etc directory, but could be installed
     elsewhere (see the --c conffile command line option). The file format is
     similar to other Unix configuration files - comments begin with a # char-
     acter and extend to the end of the line; blank lines are ignored.  Con-
     figuration commands consist of an initial keyword followed by a list of
     arguments, some of which may be optional, separated by whitespace.  Com-
     mands may not be continued over multiple lines. Arguments may be host
     names, host addresses written in numeric, dotted-quad form, integers,
     floating point numbers (when specifying times in seconds) and text
     strings. Optional arguments are delimited by [] in the following descrip-
     tions, while alternatives are separated by . The notation [ ... ] means
     an optional, indefinite repetition of the last item before the [ ... ].

     See the following pages for configuration and control options. While
     there is a rich set of options available, the only required option is one
     or more server, peer or broadcast commands described in the Configuration
     Options page. The Notes on Configuring NTP and Setting up a NTP page con-
     tains an extended discussion of these options.


FILES

     /etc/ntp.conf      the default name of the configuration file
     /etc/ntp.drift     the default name of the drift file
     /etc/ntp.keys      the default name of the key file


BUGS

     xntpd has gotten rather fat. While not huge, it has gotten larger than
     might be desireable for an elevated-priority daemon running on a worksta-
     tion, 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.


AUTHOR

     David L. Mills (mills@udel.edu)