Cisco NTP

The output show that there are 2 NTP Servers. If not – you can add the ntp servers like this

LabDevice#conf t
LabDevice(config)#ntp server [ip address](Server 1)
LabDevice(config)#ntp server [ip address](Server 2)
LabDevice(config)#exit
LabDevice#

LabDevice#clock set 10:10:10 1 januar 1993

LabDevice#sh clock
.10:11:10.816 UTC Fri Jan 1 1993
(if there is a dot infront – you see that the clock in not synchronized yet.
After synchronization it lookes like the next output.

LabDevice#sh clock
02:17:30.829 UTC Sat Jan 13 2013

LabDevice#sh ntp asso

address                  refclock              st    when      poll        reach        delay           offset            disp
*~40.99.153.30    146.83.8.200     3      62           64         17              1.4              6.89              1899.4
+~40.99.154.30   213.9.73.106     3      63          64           37              2.3             -5.89              1894.8
* master (synced), # master (unsynced), + selected, – candidate, ~ configured

LabDevice#sh ntp status
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 119.2092 Hz, actual freq is 119.2097 Hz, precision is 2**18
reference time is 00000000.00000000 (00:00:00.000 UTC Mon Jan 1 1900)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.00 msec, peer dispersion is 0.00 msec

now we change the primary NTP Server to a address it doesn ‘t exist.

LabDevice(config)#no ntp server 40.99.153.30
LabDevice(config)#no ntp server 40.99.154.30

LabDevice(config)#ntp server 1.2.3.4
LabDevice(config)#ntp server 40.99.154.30
LabDevice(config)#exit

With the debug command ‘debug ntp events’ and ‘debug ntp sync’ the change of the time or an adjustment of NTP will be logged.

logging output

Jan 13 02:17:30.829 UTC: NTP: synced to new peer 40.99.154.30
Jan 13 02:17:30.829 UTC: NTP: 40.99.154.30 synced to new peer
Jan 13 02:17:30.829 UTC: NTP: sync change
Jan 13 02:17:30.829 UTC: NTP: peer stratum change
Jan 13 02:17:30.829 UTC: NTP: 40.99.154.30 reachable