Iphone

I noticed that my desktops and member servers keep getting messages that a time server could not be located. I noticed that I do not see the port 123 listening when I use netstat. I am also unable to telnet to port 123 on my domain controller which is the time server from my domain. Any Ides?

Iphone

Event ID 50 - This indicates client and child DCs are using external time source or problem with either Domain Controller or Time service port.

You need to understand time sync feature in Windows properly.

It is not necessary to have a external time server. By default, your PDC domain is the authoritative time server in domain controller and it is set to sync time from External NTP server unless otherwise configured. All the clients sync time normally from their authenticated DC.

By default, only the first domain controller or so-called Root domain controller and finally so-called "PDC Emulator" is configured to be a Reliable Time Source.

If it doesn't exist you need to create it to make it ReliableTimeSource for other client computers and domain controllers.

Let me explain something:

By default client machines use *default heirarchy" to synchronize time. Clients will only sync with their own domain controllers in the domain. This is default bahviour and by design and to keep time closer between all PCs.

PDC is the 2nd highest stratum. Client will try to sync time with their own domain controller *unless* specifically you specify to do so. Becuase PDC is configured an authoritative server by default. It is configured using *ReliableTimeSource" entry in registry.

Stratum:

1 External NTP time source
2 PDC emulator of the forest root domain
3 Domain controllers in the forest root domain or PDC emulators in child domains
4 Workstations and member servers in the forest root domain or domain controllers in child domains
5 Workstations and member servers in child domains

Computers choose a time source according to a specific order of preference. This order, from most preferred to least preferred. The following table displays the preferences for Selecting a Time Source:

Preference Computer Location Reliability of Time Source
1 Parent domain controller In-site Reliable
2 Local domain controller In-site Reliable
3 Parent domain controller In-site Not reliable
4 Local PDC emulator In-site Not reliable
5 Parent domain controller Out-of-site Reliable
6 Local domain controller Out-of-site Reliable
7 Parent domain controller Out-of-site Not reliable
8 Local PDC emulator Out-of-site Not reliable

There is nothing much you need to do with *ReliableTimeSource* entry in registry. Simply edit the value and set it to 1 to make it Reliable time source for all computers in your network.

Moreover, you can also configure your PDC or Root Domain Controller to sync with hardware as a source time server but it is recommended that you configure your PDC to sync with an external time source.

How to configure an Authoritative Time server in Windows 2000:
How to configure an authoritative time server in Windows 2000

Make sure:

1. Time Service port is not being used by any other application.

2. If you had deleted a domain controller from your network, the DNS server shouldn't contain entries for old domain controller.

Open a command prompt > type SET > check *LOGONSERVER* variable. Now make sure this DC is configured to sync time from next domain controller or external time source e.i. time.windows.com.

Let us know.