centos7.2 配置内网ntp服务器进行时间同步

（一）修改/etc/ntp.conf 配置文件，注意红色部分，其他部分不需要改 

####################################################################

# 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

# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
#restrict default nomodify notrap nopeer noquery
restrict default ignore

# 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 ::1

# Hosts on local network are less restricted.
restrict 192.168.2.0 mask 255.255.255.0 nomodify notrap

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 127.127.1.0
fudge 127.127.1.0 stratum 10

#broadcast 192.168.1.255 autokey # broadcast server
#broadcastclient # broadcast client
#broadcast 224.0.1.1 autokey # multicast server
#multicastclient 224.0.1.1 # multicast client
#manycastserver 239.255.254.254 # manycast server
#manycastclient 239.255.254.254 autokey # manycast client

# 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 loopstats peerstats

# Disable the monitoring facility to prevent amplification attacks using ntpdc
# monlist command when default restrict does not include the noquery flag. See
# CVE-2013-5211 for more details.
# Note: Monitoring will not be disabled with the limited restriction flag.
disable monitor
#server time.windows.com
#server s2m.time.edu.cn
#server 0.asia.pool.ntp.org
#server 1.asia.pool.ntp.org
#server 2.asia.pool.ntp.org
#server 3.asia.pool.ntp.org
#server 127.127.1.0 iburst local clock
#restrict 192.168.2.1 mask 255.255.255.0 nomodify

###############################################################################

（二）启动service ntpd restart

chkconfig --level 345 ntpd on --添加启动

 测试

ntpdate 192.168.2.130 -地址为 ntp服务器地址

（三）客户端配置同步

crontab -e

00 */1 * * *  /usr/sbin/ntpdate 192.168.2.130;/sbin/hwclock -w