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Commands Reference, Volume 6

xntpd Daemon


Starts the Network Time Protocol (NTP) daemon. This command only applies to AIX 4.2 or later.


xntpd-a ] [  -b ] [  -d ] [  -m ] [  -c ConfigFile ] [  -e AuthenticationDelay ] [  -f DriftFile ] [  -k KeyFile ] [  -l LogFile ] [  -p pidFile ] [  -r BroadcastDelay ] [  -s StatsDirectory ] [  -t TrustedKey ] [  -v SystemVariable ] [  -V SystemVariable ]


The xntpd daemon sets and maintains a Unix system time-of-day in compliance 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, and also retains compatibility with version 1 and 2 servers as defined by RFC 1059 and RFC 1119, respectively. The xntpd daemon does all computations in fixed point arithmetic and does not require floating point code.

The xntpd daemon reads from a configuration file (/etc/ntp.conf is the default) at startup time. You can override the configuration file name from the command line. You can also specify a working, although limited, configuration entirely on the command line, eliminating the need for a configuration file. Use this method when configuring the xntpd daemon as a broadcast or multicast client, that determines all peers by listening to broadcasts at runtime. You can display the xntpd daemon internal variables with the ntpq command (Network Time Protocol (NTP) query program). You can alter configuration options with the xntpdc command.

The xntpd daemon operates in several modes, including symmetric active/passive, client/server and broadcast/multicast. A broadcast/multicast client can automatically discover remote servers, compute one-way delay correction factors and configure itself automatically. This mode makes it possible to deploy a group of workstations without specifying a configuration file or configuration details specific to its environment.

Note: When operating in a client mode running AIX 4.2.1 or later, the xntpd daemon will exit with an error if no configured servers are within 1000 seconds of local system time. Use the date or ntpdate command to set the time of a bad skewed system before starting xntpd.


-a Runs in authenticate mode
-b Listens for broadcast NTP and synchronizes to them if available.
-c ConfigFile  Specifies the name of an alternate configuration file.
-d Specifies debugging mode. This flag may occur multiple times (maximum of 10), with each occurrence indicating greater detail of display.
-e AuthenticationDelay  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.
-l LogFile  (lowercase L) Specifies the use of a log file instead of logging to syslog.
-m Listens for multicast messages and synchronizes to them if available. Assumes multicast address
-p pidFile  Specifies the name of the file to record the daemon's process id. There is no default.
-r BroadcastDelay  Specifies the default delay (in seconds) if the calibration procedure fails. Normally, the xntpd daemon automatically compensates for the network delay between the broadcast/multicast server and the client.
-s StatsDirectory  Specifies the directory to use for creating statistics files.
-t TrustedKey  Adds the specified key number to the trusted key list.
-v SystemVariable  Adds the specified system variable
-V SystemVariable  Adds the specified system variable listed by default.

Reference Clock Support

For the purposes of configuration, the xntpd daemon treats reference clocks in a manner analogous to normal NTP peers as much as possible. It refers to reference clocks by address, same as a normal peer is, though it uses an invalid IP address to distinguish them from normal peers. AIX 4.2 supports one type of reference clock, based on the system clock (type 1).

Reference clock addresses are of the form 127.127.Type.Unit where Type is an integer denoting the clock type and Unit indicates the type-specific unit number. You configure reference clocks by using a server statement in the configuration file where the HostAddress is the clock address. The key, version and ttl options are not used for reference clock support.

Reference clock support provides the fudge command, which configures reference clocks in special ways. This command has the following format:

fudge 127.127.Type.Unittime1 Seconds ] [ time2 Seconds ] [ stratum Integer ] [ refid Integer ] [ flag1  ] [ flag2  ] [ flag3  ] [ flag4  ]

The time1 and time2 options are in fixed point seconds and used in some clock drivers as calibration constants.

The stratum option is a number in the range zero to 15 and used to assign a nonstandard operating stratum to the clock. Since the xntpd daemon adds one to the stratum of each peer, a primary server ordinarily displays stratum one. In order to provide engineered backups, use the stratum option to specify the reference clock stratum as greater than zero. Except where noted, this option applies to all clock drivers.

The refid option is an ASCII string in the range one to four characters and used to assign a nonstandard reference identifier to the clock.

The binary flags: flag1, flag2, flag3 and flag4 are for customizing the clock driver. The interpretation of these values, and whether they are used at all, is a function of the needs of the particular clock driver.

Exit Status

This command returns the following exit values:

0 Successful completion.
>0 An error occurred.


Access Control: You must have root authority to run this command.

Auditing Events: N/A


  1. To start the xntpd daemon, enter:

    startsrc -s xntpd
  2. To stop the xntpd daemon, enter:

    stopsrc -s xntpd
  3. To use the authentication key file /etc/ntp.new.keys when running the xntpd daemon, enter:

    /usr/sbin/xntpd -k /etc/ntp.new.keys


/usr/sbin/xntpd Contains the xntpd daemon.
/etc/ntp.conf Contains the default configuration file.
/etc/ntp.drift Contains the default drift file.
/etc/ntp.keys Contains the default key file.

Related Information

The ntpq, ntpdate, ntptrace, and xntpdc commands.

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