yum安装ntp服务

一.安装NTP软件包：

yum -y install ntp /*yum安装NTP服务*/

chkconfig --add ntpd /*添加NTP*/

chkconfig ntpd on /*开机自启动NTP*/

二.修改NTP配置文件：

vi /etc/ntp.conf

***************************************************************

# For more information about this file, see the man pages

# ntp.conf(5), ntp_acc(5), ntp_auth(5), ntp_clock(5), ntp_misc(5), ntp_mon(5).

driftfile /var/lib/ntp/drift

restrict default ignore 设置默认策略为拒绝所有访问方式的请求

# Permit time synchronization with our time source, but do not

# permit the source to query or modify the service on this system.

restrict default kod nomodify notrap nopeer noquery

restrict -6 default kod nomodify notrap nopeer noquery

# Permit all access over the loopback interface. This could

# be tightened as well, but to do so would effect some of

# the administrative functions.

restrict 127.0.0.1

restrict -6 ::1

Hosts on local network are less restricted.

restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap 允许局域网内机器同步时间

# Use public servers from the pool.ntp.org project.

# Please consider joining the pool (http://www.pool.ntp.org/join.html).

server 0.CentOS.pool.ntp.org

server 1.centos.pool.ntp.org 设置同步服务器

server 2.centos.pool.ntp.org

server 127.127.1.0 # local clock

fudge 127.127.1.0 stratum 10 外界同步源无法联系时，使用本地时间为同步服务

# Enable public key cryptography.

#crypto

includefile /etc/ntp/crypto/pw

# Key file containing the keys and key identifiers used when operating

# with symmetric key cryptography.

keys /etc/ntp/keys

# Specify the key identifiers which are trusted.

#trustedkey 4 8 42

# Specify the key identifier to use with the ntpdc utility.

#requestkey 8

# Specify the key identifier to use with the ntpq utility.

#controlkey 8

# Enable writing of statistics records.

#statistics clockstats cryptostats loops

***************************************************************

时间同步

命令：

# ntpdate ip (同步时间服务器ip)

#hwclock -w //将时间写入硬件

例子

ntpdate 210.167.182.10

同步时间服务器：

server

ntp-sop.inria.frserver 210.72.145.44(中国国家授时中心服务器IP地址)

server ntp.sjtu.edu.cn(上海交通大学网络中心NTP服务器地址)

执行：

# ntpdate 210.167.182.10 (同步时间服务器ip)

#hwclock -w //将时间写入硬件