NAME

ntpd - NTP daemon program

SYNOPSIS

ntpd [-flag [value]]... [--opt-name [[=| ]value]]...

All arguments must be options.

DESCRIPTION

This manual page briefly documents the ntpd command.

OPTIONS

-4, --ipv4

Force IPv4 DNS name resolution. This option must not appear in combination with any of the following options: ipv6.

 

Force DNS resolution of following host names on the command line to the IPv4 namespace.

-6, --ipv6

Force IPv6 DNS name resolution. This option must not appear in combination with any of the following options: ipv4.

 

Force DNS resolution of following host names on the command line to the IPv6 namespace.

-a, --authreq

Require crypto authentication. This option must not appear in combination with any of the following options: authnoreq.

 

Require cryptographic authentication for broadcast client, multicast client and symmetric passive associations. This is the default.

-A, --authnoreq

Do not require crypto authentication. This option must not appear in combination with any of the following options: authreq.

 

Do not require cryptographic authentication for broadcast client, multicast client and symmetric passive associations. This is almost never a good idea.

-b, --bcastsync

Allow us to sync to broadcast servers.

 

-c string, --configfile=string

configuration file name.

 

The name and path of the configuration file, /etc/ntp.conf by default.

-d, --debug-level

Increase output debug message level. This option may appear an unlimited number of times.

 

Increase the debugging message output level.

-D string, --set-debug-level=string

Set the output debug message level. This option may appear an unlimited number of times.

 

Set the output debugging level. Can be supplied multiple times, but each overrides the previous value(s).

-f string, --driftfile=string

frequency drift file name.

 

The name and path of the frequency file, /etc/ntp.drift by default. This is the same operation as the driftfile driftfile configuration specification in the /etc/ntp.conf file.

-g, --panicgate

Allow the first adjustment to be Big. This option may appear an unlimited number of times.

 

Normally, ntpd exits with a message to the system log if the offset exceeds the panic threshold, which is 1000 s by default. This option allows the time to be set to any value without restriction; however, this can happen only once. If the threshold is exceeded after that, ntpd will exit with a message to the system log. This option can be used with the -q and -x options. See the tinker configuration file directive for other options.

-i string, --jaildir=string

Jail directory.

 

Chroot the server to the directory jaildir This option also implies that the server attempts to drop root privileges at startup. You may need to also specify a -u option. This option is only available if the OS supports adjusting the clock without full root privileges. This option is supported under NetBSD (configure with --enable-clockctl ) and Linux (configure with --enable-linuxcaps ).

-I iface, --interface=iface

Listen on an interface name or address. This option may appear an unlimited number of times.

 

Open the network address given, or all the addresses associated with the given interface name. This option may appear multiple times. This option also implies not opening other addresses, except wildcard and localhost. This option is deprecated. Please consider using the configuration file interface command, which is more versatile.

-k string, --keyfile=string

path to symmetric keys.

 

Specify the name and path of the symmetric key file. /etc/ntp.keys is the default. This is the same operation as the keys keyfile configuration file directive.

-l string, --logfile=string

path to the log file.

 

Specify the name and path of the log file. The default is the system log file. This is the same operation as the logfile logfile configuration file directive.

-L, --novirtualips

Do not listen to virtual interfaces.

 

Do not listen to virtual interfaces, defined as those with names containing a colon. This option is deprecated. Please consider using the configuration file interface command, which is more versatile.

-M, --modifymmtimer

Modify Multimedia Timer (Windows only).

 

Set the Windows Multimedia Timer to highest resolution. This ensures the resolution does not change while ntpd is running, avoiding timekeeping glitches associated with changes.

-n, --nofork

Do not fork.

 

-N, --nice

Run at high priority.

 

To the extent permitted by the operating system, run ntpd at the highest priority.

-p string, --pidfile=string

path to the PID file.

 

Specify the name and path of the file used to record ntpd's process ID. This is the same operation as the pidfile pidfile configuration file directive.

-P number, --priority=number

Process priority. This option takes an integer number as its argument.

 

To the extent permitted by the operating system, run ntpd at the specified sched_setscheduler(SCHED_FIFO) priority.

-q, --quit

Set the time and quit.

 

ntpd will exit just after the first time the clock is set. This behavior mimics that of the ntpdate program, which is to be retired. The -g and -x options can be used with this option. Note: The kernel time discipline is disabled with this option.

-r string, --propagationdelay=string

Broadcast/propagation delay.

 

Specify the default propagation delay from the broadcast/multicast server to this client. This is necessary only if the delay cannot be computed automatically by the protocol.

--saveconfigquit=string

Save parsed configuration and quit.

 

Cause ntpd to parse its startup configuration file and save an equivalent to the given filename and exit. This option was designed for automated testing.

-s string, --statsdir=string

Statistics file location.

 

Specify the directory path for files created by the statistics facility. This is the same operation as the statsdir statsdir configuration file directive.

-t tkey, --trustedkey=tkey

Trusted key number. This option may appear an unlimited number of times.

 

Add a key number to the trusted key list.

-u string, --user=string

Run as userid (or userid:groupid).

 

Specify a user, and optionally a group, to switch to. This option is only available if the OS supports adjusting the clock without full root privileges. This option is supported under NetBSD (configure with --enable-clockctl ) and Linux (configure with --enable-linuxcaps ).

-U number, --updateinterval=number

interval in seconds between scans for new or dropped interfaces. This option takes an integer number as its argument.

 

Give the time in seconds between two scans for new or dropped interfaces. For systems with routing socket support the scans will be performed shortly after the interface change has been detected by the system. Use 0 to disable scanning. 60 seconds is the minimum time between scans.

--var=nvar

make ARG an ntp variable (RW). This option may appear an unlimited number of times.

 

--dvar=ndvar

make ARG an ntp variable (RW|DEF). This option may appear an unlimited number of times.

 

-x, --slew

Slew up to 600 seconds.

 

Normally, the time is slewed if the offset is less than the step threshold, which is 128 ms by default, and stepped if above the threshold. This option sets the threshold to 600 s, which is well within the accuracy window to set the clock manually. Note: Since the slew rate of typical Unix kernels is limited to 0.5 ms/s, each second of adjustment requires an amortization interval of 2000 s. Thus, an adjustment as much as 600 s will take almost 14 days to complete. This option can be used with the -g and -q options. See the tinker configuration file directive for other options. Note: The kernel time discipline is disabled with this option.

--usepcc

Use CPU cycle counter (Windows only).

 

Attempt to substitute the CPU counter for QueryPerformanceCounter. The CPU counter and QueryPerformanceCounter are compared, and if they have the same frequency, the CPU counter (RDTSC on x86) is used directly, saving the overhead of a system call.

--pccfreq=string

Force CPU cycle counter use (Windows only).

 

Force substitution the CPU counter for QueryPerformanceCounter. The CPU counter (RDTSC on x86) is used unconditionally with the given frequency (in Hz).

-?, --help

Display extended usage information and exit.

-!, --more-help

Extended usage information passed thru pager.

- [{v|c|n}], --version[={v|c|n}]

Output version of program and exit. The default mode is `v', a simple version. The `c' mode will print copyright information and `n' will print the full copyright notice.

OPTION PRESETS

Any option that is not marked as not presettable may be preset by loading values from environment variables named:
NTPD_<option-name> or NTPD

AUTHOR

David L. Mills and/or others Please send bug reports to: http://bugs.ntp.org, bugs@ntp.org

see html/copyright.html

This manual page was AutoGen-erated from the ntpd option definitions.