Local NTP time server

About NTP

NTP ( networktime Protocol UTC 0.1ms In most places on the Internet its accuracy can be achieved 1-50ms .

NTP The server is using NTP the protocol provides time synchronization services.

NTP Server Installation

View system comes with NTP

[Email protected] ~]# Rpm-qa ntpntp-4.2.6p5-5.el6.centos.x86_64

If not, install

[[email protected] ~]# yum-y install NTP

Configuring the NTP Service

[[email protected] ~]# vim/etc/ntp.conf# restrict default kod nomodify notrap nopeernoqueryrestrict default nomodify# nom The Odify client can synchronize the # default time synchronization source comment instead to the available source # server 0.centos.pool.ntp.org iburst# server 1.centos.pool.ntp.org iburst# server 2. centos.pool.ntp.org iburst# server 3.centos.pool.ntp.org iburstserver ntp1.aliyun.comserver time.nist.gov

Start the NTP server

If scheduled tasks have time synchronization, commenting first, the two usages will conflict.

[[email protected] ~]# crontab-e# time sync by syaving at 2010-8-8#*/5 * * * */usr/sbin/ntpdate TIME.NIST.GOV>/DEV/NU ll 2>&1

[[email protected] ~]# /etc/init.d/ntpd startstarting ntpd:                                               [  OK  ][[email protected] ~]# ntpq -p     remote           refid       st t when poll reach   delay  offset   jitter==============================================================================* Ntp1.aliyun.com 10.137.38.86     2 u  22   64     1 525.885  -42.367   0.000[[email protected] ~ ]# ntpstatsynchronised to ntp server  (110.75.186.247)  atstratum 3   timecorrect to within  4257 ms   pollingserver every 64 s[[email protected] ~]#  ntpdate 10.0.0.130 7 Dec18:43:07 ntpdate[26950]: the NTP socket  Is in use, exiting

Client time synchronization

The client will wait a few minutes and then start with the new NTP The server makes time synchronization, otherwise it prompts no server suitable for Synchronizationfound error.

[[Email protected] ~]# # ntpdate 10.0.0.130 7 dec18:40:16 ntpdate[1453]: Step time server 10.0.0.130 offset 40.880807 sec

Put the command into a scheduled task.

Note: You need to comment out the previous timer task

[[email protected] ~]# crontab-e# time sync by syaving at 2010-8-8*/5 * * * * ntpdate 10.0.0.130 >/dev/null2>&1

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Local NTP time server