Router cant sync with Ntp serer in centOS 7

[mashrursakib]

Please find the outputs from the router below:

Ntp server IP address: 10.64.15.94

RTR-LINK-DC#show ntp associations detail

10.64.15.94 configured, ipv4, insane, invalid, unsynced, stratum 16

ref ID .INIT., time 00000000.00000000 (00:00:00.000 UTC Mon Jan 1 1900)

our mode client, peer mode unspec, our poll intvl 1024, peer poll intvl 1024

root delay 0.00 msec, root disp 0.00, reach 0, sync dist 15946.65

delay 0.00 msec, offset 0.0000 msec, dispersion 15937.50, jitter 0.00 msec

precision 2**10, version 4

assoc id 11740, assoc name 10.64.15.94

assoc in packets 0, assoc out packets 18, assoc error packets 0

org time E1614F4C.6978D620 (11:28:12.412 UTC Mon Oct 28 2019)

rec time 00000000.00000000 (00:00:00.000 UTC Mon Jan 1 1900)

xmt time 00000000.00000000 (00:00:00.000 UTC Mon Jan 1 1900)

filtdelay =     0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00

filtoffset =    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00

filterror =  16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0

minpoll = 6, maxpoll = 10

RTR-LINK-DC#show ntp associations

  address         ref clock       st   when   poll reach  delay  offset   disp

 ~10.64.15.94     .INIT.          16      -   1024     0  0.000   0.000 15937.

 * sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured

RTR-LINK-DC#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 349800 (1/100 of seconds), resolution is 4000

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 52.48 msec, peer dispersion is 0.00 msec

loopfilter state is 'NSET' (Never set), drift is 0.000000000 s/s

system poll interval is 8, never updated.

RTR-LINK-DC#show ntp conf

RTR-LINK-DC#show ntp config

 ntp server 10.64.15.94

RTR-LINK-DC#show ntp pac

RTR-LINK-DC#show ntp packets

Ntp In packets                  :  0

Ntp Out packets                 :  23

Ntp bad version packets         :  0

Ntp protocol error packets      :  0

RTR-LINK-DC#

Note: i can ping the router ip addrees from ntp server but cant ping from router to ntp server.

Please help me in this regards.

[paul driver]

Hello
Sounds like a possible access-list negating initiation of traffic from the router to ntp server, from the output posted the reachability/delay look okay but dispersion is high..

You could try creating an access-list and enable a debug to clarify...Post the output of the debug.

example:
conf t
ip access-list extended 110
permit ip any host 10.64.15.94
permit ip host 10.64.15.94 any

end

debug ip packet detail 110
debug ntp events
debug ntp sync

[mashrursakib]

Hello everyone,

Thank you for your valuable findings.

Now i am able to ping ntp server from router and vice versa. Still router clock is not syncing with the ntp server.  

[Deepak Kumar]

Hi,

Please share some logs as sho ip interface brief, Sho ip route, sho ip access-list and some debugs as requested by mr @paul driver.

I look as a packet dropped by ACL on the router or on the path or wrong routing configuration as you are not able to establish two-way communication. 

[Georg Pauwen]

Hello,

try and manually set the time as close as possible to the real time using the exec command 'clock set', sometimes that helps synchronizing with the NTP server...

[paul driver]

Hello

Can you please post the outputs of the debugs
Is this an authoritive server - have you tried instead - ntp peer xxx ,Also try clearing the clock period and let the router choose its own vlaue -  no ntp clock period