Windows – NTP doesn’t sync

ntpntpdwindows

I'm using Meinberg NTP to sync the time in a VPS.
The clock refuses to sync – there's a ~30s shift comparing to other servers. Also
ntpq -p is continuously showing zeros for reach, delays and jitters, which means something's wrong…

Actions I've taken which didn't help:

  • Restarted the NTP service using a script that comes with Meinberg NTP
  • Added port 123 for UDP and TCP as an exception port to Windows Firewall
  • Added Meinberk NTP executables as an exception program to Windows Firewall
  • Completely disabled Windows Firewall
  • validated iburst appears after each server listed in the configuration file
  • Restarted the server

The OS is a Windows Server Standard SP2 32bit.

What did I miss?

UPDATE 1

Here's ntpq -p result:

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 voxl-nyc-21.ser .INIT.          16 u    -   64    0    0.000    0.000   0.000
 sola-sea-04.ser .INIT.          16 u    -   64    0    0.000    0.000   0.000
 207.32.191.59   .INIT.          16 u    -   64    0    0.000    0.000   0.000

UPDATE 2
Turns out that in addition to the Windows Firewall, our VPS provider has blocked all UDP communication to our VPS instance. After opening UDP port 123 it worked flawlessly.

Best Answer

Now it seems you're not communicating with your peers. Either they're not up, not reachable, or a firewall or similar device is blocking UDP port 123.

207.32.191.59 appears to be a working stratum 2 server to me, so if the machine otherwise has working Internet access, I'd bet on a firewall.

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