ntp.conf(5) [ultrix man page]
ntp.conf(5) File Formats Manual ntp.conf(5) Name ntp.conf - Network Time Protocol configuration file Description The file is the configuration file for the Network Time Protocol (NTP) daemon, This file must be configured on your system before running Any host names that you specify in the file must have an entry in the file, or an entry in the master database, if the database is being served to your system by BIND/Hesiod or Yellow Pages. The file has four entry formats: trusting no This entry guarantees that your system synchronizes only to the NTP servers identified in the peer and server entries specified. Dig- ital recommends that all systems include the entry. peer server This entry identifies server as one of the NTP servers that your system trusts, and from which your system will accept time synchro- nization. Your system may also provide time synchronization to this server. Servers can be identified by host name or internet address. NTP servers should be configured with entries. server server This entry identifies server as one of the NTP servers that your system trusts, and from which your system will accept time synchro- nization. Your system can not provide time synchronization to this server. Servers can be identified by host name or internet address. NTP clients should be configured with entries. peer /dev/null LOCL 1 -5 local This entry identifies your system as a local reference clock. A local reference clock is the most accurate system clock available at your site. If you receive time synchronization from the Internet NTP service, you should not include this entry on any of your sys- tems. At most, one system in a set of nodes running should be identified as a local reference clock. A host which specifies this entry should not specify any or entries. Examples This is a sample configuration file for an NTP client which receives time synchronization from the NTP servers: and Lines beginning with a number sign (#) are comments. # # NTP Configuration File # This file is mandatory for the ntpd daemon # # # # ** A L L ** # # "trusting no" prevents this host from synchronizing # to any host that is not listed below. It is recommended # that all hosts include the line "trusting no". # trusting no # # # ** S E R V E R ** # # If you are configuring a server, use "peer" entries to # synchronize to other NTP servers. For example, server1, # server2, and server3. # #peer server1 #peer server2 #peer server3 # # # # # ** C L I E N T ** # # If you are configuring a client, use "server" entries to # synchronize to NTP servers. For example, server1, server2, # and server3. # server server1 server server2 server server3 # # # # ** L O C A L R E F E R E N C E C L O C K ** # # If you are configuring a local reference clock, include the # following entry and the "trusting no" entry ONLY. # #peer /dev/null LOCL 1 -5 local # See Also ntp(1), ntpd(8), ntpdc(8) RFC 1129--Internet time synchronization: The Network Time Protocol Introduction to Networking and Distributed System Services ntp.conf(5)
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NTPD.CONF(5) File Formats Manual NTPD.CONF(5) 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 sen- sor 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 syn- chronize 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 syn- chronize 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 . $Mdocdate: October 2 2007 $ NTPD.CONF(5)