yum install ntp ntpdate
vi /etc/ntp.conf
 
 
允许查询的客户端网端
<blockquote>restrict 172.16.0.0 mask 255.255.0.0 nomodify notrap</blockquote>
 
 
 
chkconfig ntpd on
chkconfig ntpdate on
service ntpd start
service ntpdate start
iptables -I INPUT 行号 -m state --state NEW -m udp -p udp --dport 123 -j ACCEPT
service iptables save
 
在客户端测试
ntpq -p
ntpdate ntp.xxxx.com