NTP synchronization problem.

[tanzeemsarwar11@gmail.com]

An NTP servere confugured on VM. i have multiple switches in  my network i.e 3550,3560,3750,4948. I configured NTP server on all these switches to sycnchronize the time. works perfectly. but unfortunately its stops synchronization on some of switches and don't sync time even after re configuring it.

I configure it using the following command.

ntp server x.x.x.x

[marce1000]

 - How do you conclude it's ntp sometimes stop syncing on some switches. Provide sample output which makes you draw this conclusion (e.g.).

M.

[tanzeemsarwar11@gmail.com]

i dont see any logs about this but i must tell you that NTP is ping able.

what else could be the cause?

[Sheraz.Salim]

I have seen this issue where NTP server is ping able but switch/router does not syn with NTP server. 

1. Make sure if there is a firewall in between than ntp port 123 is allowed.

2. Manual set the time on the client switch/router as shown in the ntp server. Once this has done wait up to 15 or some time 20 min to syn them.

as said above I came across many time the trick was point no 2

[johnd2310]

Hi,

Where is the NTP server getting its time from?  Check that the time on the NTP server is correct.

Thanks

John