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Cisco 891 NTP: "Clock is unsynchronized"

lmartin80
Level 1
Level 1

Hi,

I have a Cisco 891 router that is not synchronizing with NTP servers.

Four NTP servers are specified in the config:

Router#show running-config | include ntp
ntp update-calendar
ntp server 0.pool.ntp.org
ntp server 1.pool.ntp.org
ntp server 2.pool.ntp.org
ntp server 3.pool.ntp.org

These NTP servers are accessible from the router:

Router#ping 0.pool.ntp.org
Translating "0.pool.ntp.org"...domain server (8.8.8.8) [OK]

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 209.114.111.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 84/84/88 ms

However, the router does not synchronize to them:

Router#show ntp associations 

  address         ref clock       st   when   poll reach  delay  offset   disp
 ~104.236.52.16   .INIT.          16      -   1024     0  0.000   0.000 15937.
 ~142.54.181.202  .INIT.          16      -   1024     0  0.000   0.000 15937.
 ~216.152.240.220 .INIT.          16      -   1024     0  0.000   0.000 15937.
 ~198.211.106.151 .INIT.          16      -   1024     0  0.000   0.000 15937.
 * sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured
Router#show ntp status 
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 249.9949 Hz, precision is 2**21
ntp uptime is 40983000 (1/100 of seconds), resolution is 4016
reference time is 00000000.00000000 (19:00:00.000 EST Thu Dec 31 1899)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 6145.11 msec, peer dispersion is 0.00 msec
loopfilter state is 'FSET' (Drift set from file), drift is 0.000020440 s/s
system poll interval is 8, never updated.

How can I make the router synchronize with NTP?

Thanks

1 Accepted Solution

Accepted Solutions

Marvin Rhoads
Hall of Fame
Hall of Fame

Most likely something (most commonly a firewall) between the router and the public NTP server is blocking ntp (udp/123).

View solution in original post

2 Replies 2

Marvin Rhoads
Hall of Fame
Hall of Fame

Most likely something (most commonly a firewall) between the router and the public NTP server is blocking ntp (udp/123).

Thanks

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