Whenever we talks about cisco routers and how to set clock or accurate time on routers it becomes so important because a variety of services depend on it. We need to monitor our routers and secure our routers through server configuration.We use to configure syslog server for monitoring routers log and incident happening over routers.The logging service shows each log entry with the date and time and all details which are directly or indirectly related to NTP Server.It becomes very critical if you’re trying to track a specific incident or troubleshoot a problem.
Cisco routers have two types of clocks :
A battery-powered hardware clock, referenced as the ‘calendar’ in the IOS CLI, and
a software clock, referenced as the ‘clock’ in the IOS CLI.
The software clock is the primary source for time data and runs from the moment the system is up and running. The software clock can be updated from a number of sources.
Now to show ntp server-client configuration i have taken below topology diagram.
Step-1:First configure ip address on routers.
Router>enable Router#config t Enter configuration commands, one per line. End with CNTL/Z. Router(config)#host r1 r1(config)#int fa0/0 r1(config-if)#ip add 126.96.36.199 255.0.0.0 r1(config-if)#no shut r1(config-if)# r1(config-if)#exit
Step-2: Now see time before NTP Configuration
r1#show clock *0:8:25.144 UTC Mon Mar 1 1993 r1#
Step-3:Now going to configure NTP Server
Step-4:Now again go to Router and setup NTP Client.
r1#config t Enter configuration commands, one per line. End with CNTL/Z. r1(config)#ntp server 188.8.131.52 r1(config)#exit
Step-5:Now again see the time again to confirm NTP Configured or not.
*11:39:49.172 UTC Tue Nov 24 2015 r1#
r1#show ntp status Clock is synchronized, stratum 2, reference is 184.108.40.206 nominal freq is 250.0000 Hz, actual freq is 249.9990 Hz, precision is 2**19 reference time is D9DC8200.000000DB (11:31:12.219 UTC Mon Nov 30 2015) clock offset is 0.00 msec, root delay is 0.00 msec root dispersion is 0.02 msec, peer dispersion is 0.02 msec.