NAME¶
ntpd.conf - Network Time Protocol daemon configuration file
DESCRIPTION¶
This manual page describes the format of the
ntpd(8) configuration file.
The optional
weight keyword permits finer control over the relative
importance of time sources (servers or sensor devices). Weights are specified
in the range 1 to 10; if no weight is given, the default is 1. A server with a
weight of 5, for example, will have five times more influence on time offset
calculation than a server with a weight of 1.
ntpd.conf has the following format:
Empty lines and lines beginning with the `#' character are ignored.
Keywords may be specified multiple times within the configuration file. They are
as follows:
- listen on address
- OpenNTPd has the ability to sync the local clock to remote
NTP servers and, if this directive is specified, can act as NTP server
itself, redistributing the local clock.
Specify a local IP address or a hostname the ntpd(8) daemon should
listen on to enable remote clients synchronization. If it appears multiple
times, ntpd(8) will listen on each given address. If `*' is given
as an address, ntpd(8) will listen on all local addresses.
ntpd(8) does not listen on any address by default. For example:
listen on *
or
listen on 127.0.0.1
listen on ::1
- sensor device [correction
microseconds] [weight
weight-value]
- Specify a timedelta sensor device ntpd(8) should
use. The sensor can be specified multiple times: ntpd(8) will use
each given sensor that actually exists. Non-existent sensors are ignored.
If `*' is given as device name, ntpd(8) will use all timedelta
sensors it finds. ntpd(8) does not use any timedelta sensor by
default. For example:
sensor *
sensor udcf0
An optional correction in microseconds can be given to compensate for the
sensor's offset. The maximum correction is 127 seconds. For example, if a
DCF77 receiver is lagging 15ms behind actual time:
sensor udcf0 correction 15000
- server address [weight
weight-value]
- Specify the IP address or the hostname of an NTP server to
synchronize to. If it appears multiple times, ntpd(8) will try to
synchronize to all of the servers specified. If a hostname resolves to
multiple IPv4 and/or IPv6 addresses, ntpd(8) uses the first
address. If it does not get a reply, ntpd(8) retries with the next
address and continues to do so until a working address is found. For
example:
server 10.0.0.2 weight 5
server ntp.example.org weight 1
To provide redundancy, it is good practice to configure multiple servers. In
general, best accuracy is obtained by using servers that have a low
network latency.
- servers address [weight
weight-value]
- As with server, specify the IP address or hostname
of an NTP server to synchronize to. If it appears multiple times,
ntpd(8) will try to synchronize to all of the servers specified.
Should the hostname resolve to multiple IP addresses, ntpd(8) will
try to synchronize to all of them. For example:
servers pool.ntp.org
FILES¶
- /etc/openntpd/ntpd.conf
- default ntpd(8) configuration file
SEE ALSO¶
ntpd(8),
sysctl(8)
HISTORY¶
The
ntpd.conf file format first appeared in OpenBSD 3.6 .