xntpd - Network Time Protocol (NTP) daemon
/usr/sbin/xntpd [-abdgmx] [-c conffile] [-e auth_delay] [-f driftfile] [-k
keyfile] [-l logfile] [-p pidfile] [-r broaddelay] [-s statdir] [-t trust-
edkey] [-v sysvar] [-V def_sysvar]
-a Runs in authenticate mode.
-b Listens for broadcast NTP and synchronizes to this if available.
-d Specify debugging mode. This option may occur multiple times, with each
occurence indicating greater detail of display.
-g Allows xntpd to correct any time difference, including differences
greater than 1000 seconds.
-m Listens for multicast messages and synchronizes to them if available
(requires multicast kernel).
-x Prevents xntpd from setting the system time backward. In NTP version
3, the default allows xntpd to set the system time backward.
Specifies an alternate configuration file.
Specifies the time (in seconds) it takes to compute the NTP encryption
field on this computer.
Specifies the location of the drift file.
Specifies the location of the file which contains the NTP authentica-
tion keys. See ntp.keys(4) for information on the authentication key
Specifies a log file instead of logging to syslog.
Specifies the name of the file to record the daemon's process id.
Specifies the default round trip delay (in seconds) to be used if the
daemon cannot automatically compensate for network delay when synchron-
izing to broadcasts.
Specifies the directory in which to create statistics files.
Adds a key number to the trusted key list.
Adds a system variable.
Adds a system variable listed by default.
The xntpd daemon maintains a system's time-of-day in agreement with Inter-
net standard time servers. The xntpd daemon is a complete implementation
of the Network Time Protocol (NTP) version 3 standard as defined by RFC
1305, but also retains compatibility with version 1 and version 2 servers
as defined by RFC 1059 and RFC 1119, respectively.
The xntpd daemon does all computations in fixed point arithmetic and
requires no floating point code. The computations done in the protocol and
clock adjustment code are carried out with high precision and with atten-
tion to the details that might introduce systematic bias into the computa-
tions, to try to maintain an accuracy suitable for synchronizing with even
the most precise external time source.
The xntpd daemon reads its configuration from a file at startup time. The
default configuration file is /etc/ntp.conf. The xntpd daemon can be moni-
tored and configuration options altered while the daemon is running by
using either the ntpq(8) or the xntpdc(8) program.
The xntpd daemon includes support for several commercially available exter-
nal reference clocks. See ntp.conf(4) for information on the use and confi-
guration of reference clocks.
The Tru64 UNIX operating system also provides the NTP_TIME and MICRO_TIME
kernel options to allow greater accuracy and time resolution. See
ntp_intro(7) and Network Administration: Services for more information.
Default name of the configuration file
Conventional name of the drift file
Conventional name of the key file
Commands: ntp(1), ntpdate(8), ntpq(8), xntpdc(8)
Files: ntp.conf(4), ntp.keys(4)
Network Administration: Services
Written by Dennis Ferguson at the University of Toronto. Text amended by
David Mills at the University of Delaware.