ntp.conf.5

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH ntp.conf 5
.SH Name
ntp.conf \- Network Time Protocol configuration file
.SH Description
The 
.PN /etc/ntp.conf 
.NXR "ntp.conf file" "described"
.NXR "named configuration file" "described"
file is the configuration file for the Network
Time Protocol (NTP) daemon, 
.PN ntpd .  
This file must be configured on your system before running 
.PN ntpd .  You must be superuser to modify this file .
.NT
Any host names that you specify in
the 
.PN /etc/ntp.conf
file must have an entry in the
.PN /etc/hosts
file, or an entry in the master
.PN hosts
database, if the database is being served to your system
by BIND/Hesiod or Yellow Pages.
.NE
.PP          
The 
.PN /etc/ntp.conf 
file has four entry formats:
.IP "trusting no" 5
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 
.PN "trusting no" 
entry.
.IP "peer \fIserver\fP"
This entry identifies \fIserver\fP as one of the NTP servers
that your system trusts, and from which your system
will accept time synchronization.   Your system may also
provide time synchronization to this server.  Servers
can be identified by host name or internet address.  
.IP
NTP servers should be configured with 
.PN peer
entries.  
.IP "server \fIserver\fP"
This entry identifies \fIserver\fP as one of the NTP servers
that your system trusts, and from which your system
will accept time synchronization.  Your system can not
provide time synchronization to this server.  Servers 
can be identified by host name or internet address.
.IP
NTP clients should be configured with 
.PN server
entries.
.nf
.IP "peer   /dev/null       LOCL    1       \-5      local"
.fi
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 systems.  
At most, one system in a set of nodes running 
.PN ntpd 
should be identified as a local reference clock. 
.IP
A host which specifies this entry should not specify any
.PN peer
or 
.PN server
entries.
.SH Examples
This is a sample configuration file for an NTP client which receives 
time synchronization from the NTP servers: 
.PN server1 , 
.PN server2, 
and  
.PN server3.
Lines beginning with a number sign (#) are comments.
.EX
#
#               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
# 	        
.EE
.SH See Also
ntp(1), ntpd(8), ntpdc(8)
.br
\fIRFC 1129\(emInternet time synchronization:  The Network Time Protocol\fP
.br
.I "Introduction to Networking and Distributed System Services"