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time synchronization problem

Occasional Visitor

time synchronization problem

here in short my problem:

-Core Router 3400CL 6VLANS (Number 0-5)
-inside each VLAN 2-3 Switches Procurve Type 2524 or 2824
- existing Windows Time Server in VLAN 0

Time is correct on all Switches in VLAN0
an on the core router

I am not able to synchronize time on
all other switches in VLAN 1-5

What can I do? What's going wrong?

Trusted Contributor

Re: time synchronization problem


First of all,and that is all I can say right now based on the info you supply, do these switches have connectivity to the Time Server. Can you ping it from these switches?

Regards, Ardon
ProCurve Networking Engineer
Les Ligetfalvy
Esteemed Contributor

Re: time synchronization problem

Since they are in another VLAN, I assume they reach the time server by route. Did you set the timesync on the switches to use unicast or broadcast? Broadcast won't cross routers.
Occasional Visitor

Re: time synchronization problem

Thanks for the answers, they helped me to find out what was going wrong. Expecially the information that it should work with unicast.

The back-route from the time server was not set correctly - so now it works, but:

So that's o.k. but:
Some switches show the correct time, some others show a time 2hrs earlier. With the same time settimg:

Time Sync Method [None] : SNTP
SNTP Mode [Disabled] : Unicast
Server Address :
Poll Interval (sec) [720] : 720
Server Version [3] : 3
Time Zone [0] : 60
Daylight Time Rule [None] : Western-Europe

This seems strange.

Thomas Bianco
Honored Contributor

Re: time synchronization problem

the windows time service is really optimized to talk to other windows time services. consider using a full port of NTP.


bear in mind any NTP service will require at least a rough synchronization before it can start correcting the time. a co-worker's watch sync is all that's required to get close enough (generally within one minute) for NTP to take over.
There have been Innumerable people who have helped me. Of course, I've managed to piss most of them off.