01-25-2024 08:11 AM
Hello Community!
We have cisco router C8500L-8S4X that has NTP server configured but router ntp unsynchronized:
RTR02#show ntp status
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 250.0000 Hz, precision is 2**10
ntp uptime is 679590700 (1/100 of seconds), resolution is 4000
reference time is 00000000.00000000 (17:00:00.000 MST Wed Dec 31 1899)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 101938.60 msec, peer dispersion is 0.00 msec
loopfilter state is 'FSET' (Drift set from file), drift is 0.000000000 s/s
system poll interval is 8, never updated.
There exists no firewall or NAT between the NTP server and the router. Simultaneously, another router, which is connected to the same network and has an identical setup, does not encounter any problems. The only difference between the two routers is the 'stratum' value. The failed router has a 'stratum' value of '16', whereas the successful router has a 'stratum' value of '5'.
RTR05#show ntp status
Clock is synchronized, stratum 5, reference is x.x.x.x
nominal freq is 250.0000 Hz, actual freq is 250.0048 Hz, precision is 2**10
ntp uptime is 3209306004 (1/100 of seconds), resolution is 4000
reference time is E95CF450.4A3D7170 (07:53:04.290 MST Thu Jan 25 2024)
clock offset is 4.2751 msec, root delay is 48.67 msec
root dispersion is 134.54 msec, peer dispersion is 1.07 msec
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is -0.000019190 s/s
system poll interval is 1024, last update was 2202 sec ago.
RTR02#show ntp associations
address ref clock st when poll reach delay offset disp
~<ntp IP> .TIME. 16 - 64 0 0.000 0.000 16000.
~<ntp IP> .TIME. 16 - 64 0 0.000 0.000 16000.
* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured
I can ping both ntp servers from router source port
All other configuration is the same
I run 'debu ntp all' and there is no ntp events on the router
This is my questions:
1. How to manually push a synchronization?
2. How to change stratum value?
3. Any troubleshooting steps
Thank yu!
Sincerely,
Andrey P.
01-25-2024 08:30 AM
Debug ntp packet
Share this
MHM
01-25-2024 10:32 AM
Thank you Sir MHM Cisco World again!
I found the problem
It was wrong source port assigned for 'ntp source ...'
Issue resolved
01-25-2024 11:07 AM
Friend you are so welcome
MHM
01-25-2024 09:56 AM
Hello,
what are you using as NTP server ? What do you have configured on the non-working router with regard to NTP ?
Sometimes it helps to manually set the clock to something close to the real time, using the 'clock set' command...you might want to give that a try...
01-25-2024 10:33 AM
Thank you Georg!
I found the problem
It was wrong source port assigned for 'ntp source ...'
Issue resolved now
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