Cisco 网络时间 NTP同步

NTP 同步协议配置
Tags: NTP, 时间同步, 实验, 协议
时间同步对于大的中是必须的。用来排错时看日志用的。

R1 ---------   R2---------- R3(Server)

R1:
clock timezone CHINA 8// 时区
interface Serial1/1
ip address 172.16.1.1 255.255.0.0
ntp broadcast client     配置本地路由器为NTP客户端，接受NTP的时间广播信息来配置本地时间
router rip
network 172.16.0.0
ntp server 192.168.1.3 // 指定服务器IP

R2:
clock timezone CHINA 8// 时区
interface Serial1/1
ip address 172.16.1.2 255.255.0.0
interface Serial1/3
ip address 192.168.1.2 255.255.255.0
ntp broadcast client     配置本地路由器为NTP客户端，接受NTP的时间广播信息来配置本地时间
router rip
network 172.16.0.0
network 192.168.1.0
ntp authentication-key 1 md5 cisco
ntp authenticate
ntp server 192.168.1.3

R3:
interface Serial1/3
ip address 192.168.1.3 255.255.255.0
router rip
network 192.168.1.0
clock timezone CHINA 8// 时区
ntp authentication-key 1 md5 cisco
ntp authenticate
ntp source Serial1/2      配置NTP与NTP通信的源地址
ntp master                配置自身为权威的NTP服务器

实验结果：
R1#sh clock

00:07:51.242 UTC Mon Mar 1 1993

R2#sh clock
*00:03:09.359 UTC Mon Mar 1 1993

在R3上设置：

R3#clock set 13:34:50 sep 27 2008

过几分钟（NTP协议收敛很慢，大的网络可能要等上半个---一个小时）

R1#sh clock
13:44:54.692 UTC Sat Sep 27 2008

R2#sh clock
13:44:46.638 UTC Sat Sep 27 2008

R1#sh ntp status
Clock is synchronized, stratum 9, reference is 192.168.1.3
nominal freq is 250.0000 Hz, actual freq is 249.9999 Hz, precision is 2**18
reference time is CC88B769.D3212DD4 (13:45:13.824 UTC Sat Sep 27 2008)
clock offset is -40.5541 msec, root delay is 15.95 msec
root dispersion is 1967.65 msec, peer dispersion is 1927.06 msec

R2#sh ntp status
Clock is synchronized, stratum 9, reference is 192.168.1.3
nominal freq is 250.0000 Hz, actual freq is 249.9989 Hz, precision is 2**18
reference time is CC88C252.CDB8FCFF (14:31:46.803 UTC Sat Sep 27 2008)
clock offset is -48.3540 msec, root delay is 15.93 msec
root dispersion is 77.47 msec, peer dispersion is 29.08 msec

相应的查看与调试命令：
show clock detail
show ntp associations
show ntp status
debug ntp packets
debug ntp authentications
可在客户端没用的接口关闭NTP服务。ntp disable