NTP Issues

[TheDevopsGuy]

Hi,

We currently have a hypervisor(HyperV) which is synchronizing with Googles NTP.

For some reason NTP to the hypervisor and the Domain controller works but no client is updating time.

The clients can connect to the DMC and they detect it as its NTP server.

The issue started since a powercut, I've checked about everything server side for services and related to NTP could I assume that this is possibly being filtered by a firewall in between or windows firewall on the systems?

 

[DelJo63]

It is possible

One reason for NTP synchronisation problems may be a firewall or port filter that is blocking the ports the programs use to communicate (by default UDP port 123). For example in Windows 8, check firewall settings in Control Panel -> Windows Firewall->Advanced settings.

 

[TheDevopsGuy]

It is possible

Was working prior to the powercut and I just checked clients have windows firewall disabled by a GPO

 

[TheDevopsGuy]

It could be a firewall configuration not being saved gotta check the ACL's..

 

[Gabriel Pike]

I would check permissions first. It is possible that could be the issue. Below is an example of configuration from elevated command prompt.

net stop w32time
w32tm /config /syncfromflags:manual /manualpeerlist:192.168.10.1
w32tm /config /reliable:yes
net start w32time
w32tm /resync /rediscover

You can check your configuration with:

w32tm /query /configuration

On a windows box you can manually specify the time server with net time.

net time \\nameoftimeserver /set /y

 

[TheDevopsGuy]

I would check permissions first. It is possible that could be the issue. Below is an example of configuration from elevated command prompt.

net stop w32time
w32tm /config /syncfromflags:manual /manualpeerlist:192.168.10.1
w32tm /config /reliable:yes
net start w32time
w32tm /resync /rediscover

You can check your configuration with:

w32tm /query /configuration

On a windows box you can manually specify the time server with net time.

net time \\nameoftimeserver /set /y

Will give it a go. Thing is they all sync time with a domain controller. In reality I tried a bandaid solution I am currently using the NTP of windows. Just not the Local DMC.

 

[DelJo63]

Was working prior to the powercut and I just checked clients have windows firewall disabled by a GPO

hmm; guess that's ok for testing, I would never operate Windows w/o a firewall

 

[TheDevopsGuy]

hmm; guess that's ok for testing, I would never operate Windows w/o a firewall

They're completely isolated by a cisco asa. No traffic passes except the ones which are permitted. Never had any issues SO FAR.

 

[DelJo63]

No traffic passes except the ones which are permitted.

who has control of it?

 

[TheDevopsGuy]

My CTO.