ntp.conf(5)ntp.conf(5)Namentp.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.
Digital 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 syn‐
chronization. Your system may also provide time synchronization
to this server. Servers can be identified by host name or inter‐
net 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 syn‐
chronization. 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 Inter‐
net NTP service, you should not include this entry on any of your
systems. 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 Alsontp(1), ntpd(8), ntpdc(8)
RFC 1129—Internet time synchronization: The Network Time Protocol
Introduction to Networking and Distributed System Services
ntp.conf(5)
