NTP服务器遇到的问题

在安装NTP服务器，客户端采用ntpdate遇到的问题

一、NTP服务器的安装，参考上篇博客

须要修改配置文件ntp.conf 。添加以下一行

restrict 172.22.26.111 mask 255.255.255.0 nomodify notrap

去掉或者添加下面注释

server 127.127.1.0
fudge 127.127.1.0 stratum 8

重启NTP服务器

service ntpd restart
查看端口是否存在
netstat -ulp | grep 123

须要查看防火墙是否关闭

若是iptables没有关闭，须要添加防火墙规则
iptables -A INPUT -s 172.17.14.0/24 -p udp --dport 6379 -j ACCEPT  // 172.17.14网段能够访问ntp服务器123端口
iptables -A INPUT -p udp --dport 123 -j REJECT // 其余访问123端口拒绝
service iptables save
service iptables restart

客户端经过定时任务与ntp服务器同步

crontab -e
*/5 * * * * /usr/sbin/ntpdate 172.17.14.111  && hwclock --systohc

经过命令：ntpdate 172.17.14.111 查看同步信息状况

常遇到的问题

# ntpdate -d 192.168.70.11
 4 Apr 05:26:56 ntpdate[2057]: ntpdate 4.2.4p8@1.1612-o Fri Feb 22 11:23:28 UTC 2013 (1)
Looking for host 192.168.70.11 and service ntp
host found : server.neo.com
transmit(192.168.70.11)
receive(192.168.70.11)
transmit(192.168.70.11)
receive(192.168.70.11)
transmit(192.168.70.11)
receive(192.168.70.11)
transmit(192.168.70.11)
receive(192.168.70.11)
transmit(192.168.70.11)
server 192.168.70.11, port 123
stratum 16, precision -24, leap 00, trust 000
refid [192.168.70.11], delay 0.02582, dispersion 0.00000
transmitted 4, in filter 4
reference time:    d758e781.49a1617b  Sat, Jun 28 2014 15:04:33.287
originate timestamp: d758e7ab.8db9fc66  Sat, Jun 28 2014 15:05:15.553
transmit timestamp:  d6e850a0.6b3af2bc  Fri, Apr  4 2014  5:26:56.418
filter delay:  0.02707  0.02585  0.02582  0.02582 
         0.00000  0.00000  0.00000  0.00000 
filter offset: 7378699. 7378699. 7378699. 7378699.
         0.000000 0.000000 0.000000 0.000000
delay 0.02582, dispersion 0.00000
offset 7378699.134602
 
 4 Apr 05:26:56 ntpdate[2057]: step time server 192.168.70.11 offset 7378699.134602 sec

查看配置文件

server 127.127.1.0
fudge 127.127.1.0 stratum 8

是否添加