NAME

xntpd - Network Time Protocol (NTP) daemon

SYNOPSIS

/usr/sbin/xntpd [-abdgmx] [-c conffile] [-e auth_delay]
    [-f driftfile] [-k keyfile] [-l logfile]
    [-p pidfile] [-r broaddelay] [-s statdir]
    [-t trustedkey] [-v sysvar] [-V def_sysvar]

FLAGS

-aRuns in authenticate mode. 

-bListens for broadcast NTP and synchronizes to this if available. 

-dSpecify debugging mode. This flag may occur multiple times, with each occurence indicating greater detail of display. 

-gAllows xntpd to correct any time difference, including differences greater than 1000 seconds. 

-mListens for multicast messages and synchronizes to them if available (requires multicast kernel). 

-xPrevents xntpd from setting the system time backward.  In NTP version 3, the default allows xntpd to set the system time backward. 

-c conffile
Specifies an alternate configuration file.

-e authdelay
Specifies the time (in seconds) it takes to compute the NTP encryption field on this computer.

-f driftfile
Specifies the location of the drift file.

-k keyfile
Specifies the location of the file which contains the NTP authentication keys.  See ntp.keys(4) for information on the authentication key file format. 

-l logfileSpecifies a log file instead of logging to syslog. 

-p pidfile
Specifies the name of the file to record the daemon’s process id.

-r broaddelay
Specifies the default round trip delay (in seconds) to be used if the daemon cannot automatically compensate for network delay when synchronizing to broadcasts.

-s statdir
Specifies the directory in which to create statistics files.

-t trustedkey
Adds a key number to the trusted key list.

-v sysvar
Adds a system variable.

-V def_sysvar
Adds a system variable listed by default.

DESCRIPTION

The xntpd daemon maintains a system’s time−of−day in agreement with Internet 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. 

Xntpd 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 attention to the details that might introduce systematic bias into the computations, to try to maintain an accuracy suitable for synchronizing with even the most precise external time source. 

Xntpd reads its configuration from a file at startup time.  The default configuration file is /etc/ntp.conf. The ntpsetup script automatically configures your system to run xntpd, and should be used by all systems that receive time from other NTP servers.  The xntpd daemon can be monitored and configuration options altered while the daemon is running by using either the ntpq(8) or the xntpdc(8) program. 

Xntpd includes support for several commercially available external reference clocks.  See ntp.conf(4) for information on the use and configuration of reference clocks. 

The DIGITAL 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 System Administration for more information. 

FILES

/etc/ntp.conf
Default name of the configuration file

/etc/ntp.drift
Conventional name of the drift file

/etc/ntp.keys
Conventional name of the key file

RELATED INFORMATION

Commands: ntp(1), xntpdc(8), ntpq(8), ntpdate(8)

Files:  ntp.conf(4),  ntp.keys(4)

Network Administration

HISTORY

Written by Dennis Ferguson at the University of Toronto.  Text amended by David Mills at the University of Delaware.