[root@server21 ~]# cat /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

# 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 10.1.3.0 mask 255.255.255.0 nomodify notrap      //定义只有10.1.3.0的内网访问server21

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

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

#server 0.cn.pool.ntp.org    //因为我的服务器机房所在地，对第一个域名访问速度不好 ，所以屏蔽掉他

server 3.asia.pool.ntp.org           

server 2.asia.pool.ntp.org

#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

[root@Redis_Master ~]# watch ntpq -p

Every 2.0s: ntpq -p                                                 Tue Aug 26 10:50:35 2014

 remote           refid      st t when poll reach   delay   offset  jitter

==============================================================================

 61.110.197.50   108.71.253.20    2 u   28   64    1  108.384   37.441   0.000

 194.27.44.55    62.12.173.11     2 u   28   64    1  352.688   49.994   0.000