参考
http://acooly.iteye.com/blog/1993484
对于一个联网的机器
service ntpd restart
chkconfig ntpd on
如果在内网，一台机器想做ntp服务器
@H_502_16@# For more information about this file,see the man pages
@H_502_16@# ntp.conf(5),ntp_acc(5),ntp_auth(5),ntp_clock(5),ntp_misc(5),ntp_mon(5).
driftfile /var/lib/ntp/drift
@H_502_16@# Permit time synchronization with our time source,but do not
@H_502_16@# 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
@H_502_16@# Permit all access over the loopback interface. This could
@H_502_16@# be tightened as well,but to do so would effect some of
@H_502_16@# the administrative functions.
restrict 127.0.0.1
restrict -6 ::1
@H_502_16@# Hosts on local network are less restricted.
@H_502_16@#restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
restrict 0.0.0.0 mask 0.0.0.0 nomodify notrap
@H_502_16@# Use public servers from the pool.ntp.org project.
@H_502_16@# Please consider joining the pool (http://www.pool.ntp.org/join.html).
@H_502_16@#server 0.centos.pool.ntp.org iburst
@H_502_16@#server 1.centos.pool.ntp.org iburst
@H_502_16@#server 2.centos.pool.ntp.org iburst
@H_502_16@#server 3.centos.pool.ntp.org iburst
@H_502_16@# 中国这边最活跃的时间服务器 : http://www.pool.ntp.org/zone/cn
server 210.72.145.44 perfer # 中国国家受时中心
server 202.112.10.36 # 1.cn.pool.ntp.org
server 59.124.196.83 # 0.asia.pool.ntp.org
@H_502_16@#broadcast 192.168.1.255 autokey # broadcast server
@H_502_16@#broadcastclient # broadcast client
@H_502_16@#broadcast 224.0.1.1 autokey # multicast server
@H_502_16@#multicastclient 224.0.1.1 # multicast client
@H_502_16@#manycastserver 239.255.254.254 # manycast server
@H_502_16@#manycastclient 239.255.254.254 autokey # manycast client
@H_502_16@# Enable public key cryptography.
@H_502_16@#crypto
includefile /etc/ntp/crypto/pw
@H_502_16@# Key file containing the keys and key identifiers used when operating
@H_502_16@# with symmetric key cryptography.
keys /etc/ntp/keys
@H_502_16@# Specify the key identifiers which are trusted.
@H_502_16@#trustedkey 4 8 42
@H_502_16@# Specify the key identifier to use with the ntpdc utility.
@H_502_16@#requestkey 8
@H_502_16@# Specify the key identifier to use with the ntpq utility.
@H_502_16@#controlkey 8
@H_502_16@# Enable writing of statistics records.
@H_502_16@#statistics clockstats cryptostats loopstats peerstats
如果想做ntpclient，和本地的ntp服务器同步
ntpdate -u 10.9.62.11
或者
@H_502_16@# For more information about this file,but to do so would effect some of
@H_502_16@# the administrative functions.
restrict 127.0.0.1
restrict -6 ::1
@H_502_16@# Hosts on local network are less restricted.
@H_502_16@#restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
@H_502_16@# Use public servers from the pool.ntp.org project.
@H_502_16@# Please consider joining the pool (http://www.pool.ntp.org/join.html).
@H_502_16@#server 0.centos.pool.ntp.org iburst
@H_502_16@#server 1.centos.pool.ntp.org iburst
@H_502_16@#server 2.centos.pool.ntp.org iburst
@H_502_16@#server 3.centos.pool.ntp.org iburst
server 10.9.62.11
@H_502_16@#broadcast 192.168.1.255 autokey # broadcast server
@H_502_16@#broadcastclient # broadcast client
@H_502_16@#broadcast 224.0.1.1 autokey # multicast server
@H_502_16@#multicastclient 224.0.1.1 # multicast client
@H_502_16@#manycastserver 239.255.254.254 # manycast server
@H_502_16@#manycastclient 239.255.254.254 autokey # manycast client
@H_502_16@# Enable public key cryptography.
@H_502_16@#crypto
includefile /etc/ntp/crypto/pw
@H_502_16@# Key file containing the keys and key identifiers used when operating
@H_502_16@# with symmetric key cryptography.
keys /etc/ntp/keys
@H_502_16@# Specify the key identifiers which are trusted.
@H_502_16@#trustedkey 4 8 42
@H_502_16@# Specify the key identifier to use with the ntpdc utility.
@H_502_16@#requestkey 8
@H_502_16@# Specify the key identifier to use with the ntpq utility.
@H_502_16@#controlkey 8
@H_502_16@# Enable writing of statistics records.
@H_502_16@#statistics clockstats cryptostats loopstats peerstats
