5.2.2. NTP Configuration

NTP Client:

Router(config)# ntp server 10.1.1.1
Router(config)# ntp server 10.1.1.2 prefer

NTP Server (also a client to upstream):

Router(config)# ntp server 129.6.15.28        ! External time source
Router(config)# ntp master 3                   ! Become stratum 3 server

Verification:

Router# show ntp status
Router# show ntp associations
Router# show clock

In show ntp associations, * marks the peer the router is currently synchronized to (sys.peer) and ~ marks a configured server. st is that server's stratum, and a reach of 377 (octal: all of the last eight polls answered) means it is fully reachable. show ntp status reports whether the clock is synchronized and the router's own stratum, one higher than its reference.