How to setup NTP to External NTP Server?

[Adventech]

PROBLEM:
How to Sync Windows 2008 to NTP?
How to add Authoritative NTP Server to AD?
How to setup NTP to External NTP Server?

SOLUTION:
On AD server that is running Windows server 2008 / 2008 R2 you should run command prompt with administrative rights (right click / run as administrator).

First check difference between your server and external time source (in my example pool.ntp.org)

Command: w32tm /stripchart /computer:pool.ntp.org /samples:5 /dataonly

Example:
C:\>w32tm /stripchart /computer:pool.ntp.org /samples:5 /dataonly
Tracking pool.ntp.org [194.249.198.37:123].
Collecting 5 samples.
The current time is 24.6.2011 13:29:08.
13:29:08, +08.8351541s
13:29:10, +08.7976694s
13:29:12, +08.8065559s
13:29:14, +08.7534768s
13:29:16, +08.7956427s

Confiure your server to use external NTP time source for sync:

Command: w32tm /config /manualpeerlist:pool.ntp.org,0×8, /syncfromflags:manual /reliable:yes /update

Example:
C:\>w32tm /config /manualpeerlist:pool.ntp.org,0×8, /syncfromflags:manual /update
The command completed successfully.

Force sync immediately:
Command: w32tm /resync

Example:
C:\>w32tm /resync
Sending resync command to local computer
The command completed successfully.

I will now retry the first command to see the results:

C:\>w32tm /stripchart /computer:pool.ntp.org /samples:5 /dataonly
Tracking pool.ntp.org [193.2.111.2:123].
Collecting 5 samples.
The current time is 24.6.2011 13:19:20.
13:19:20, +00.0485657s
13:19:22, +00.0415741s
13:19:24, +00.0380984s
13:19:26, +00.0342493s
13:19:28, +00.0310221s