0. Before start.

To configure NTP client you need Administrator privileges or Administartor's password. It is not possible to change configuration without sufficient privileges.

Below are several times four very similar commands with following meaning:

   - 1st line: define variable myKey with working key.
   - 2st line: show current value of parameter ( QUERY ),
   - 3nd line: add (if not defined) or change parameter to new value ( ADD ),
   - 4rd line: show new parameter value ( QUERY ).

In situation when command fails or existing value is alredy set to desired value, result of commands in second and fourth line will be the same.

Please note, that commands may be splitted to several lines depending of device browser width.

1.) Open elevated Administrator command prompt.

   - on keyboard press windows key to open start menu,
   - after start menu opens type "cmd",
   - choose option "Run As Administrator",
   - if current user has not enough privileges, password popup will open.

Command "cmd" will start in "Elevated mode". This mode is recognized with user name "Administrator" in title of cmd window. Carefully enter (copy/paste) commands below from steps 2 to 8.

2.) Change MinPollInterval from default 0xa (2^10 = 1024sec) to 0x6 (2^6 = 64sec).

   set myKey=HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Config
   REG QUERY %myKey% /v MinPollInterval
   REG ADD   %myKey% /v MinPollInterval /t REG_DWORD /d 0x6 /f
   REG QUERY %myKey% /v MinPollInterval

3.) Change MaxPollInterval from default 0xf (2^15 = 32768 sec) to 0xa (2^10 = 1024 sec).

   set myKey=HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Config
   REG QUERY %myKey% /v MaxPollInterval
   REG ADD   %myKey% /v MaxPollInterval /t REG_DWORD /d 0xa /f
   REG QUERY %myKey% /v MaxPollInterval

4.) Change Client Type to NTP.

   set myKey=HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameters
   REG QUERY %myKey% /v Type
   REG ADD   %myKey% /v Type /t REG_SZ /d NTP /f
   REG QUERY %myKey% /v Type

5.) Change NtpClient state to enabled.

   set myKey=HKLM\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient
   REG QUERY %myKey% /v Enabled
   REG ADD   %myKey% /v Enabled /t REG_DWORD /d 0x1 /f
   REG QUERY %myKey% /v Enabled

6.) Register and restart NTP service.

   w32tm /register
   net stop  w32time
   net start w32time

7.) Select IP protocol version.

In order to align server connection to your network configuration it is advisable to define IP protocol version for time synchronization. There are three possible variants - use one from list:

    For dual stacked IPv4 and IPv6 connected device(s) use:

        set myTld="pool.chrony.eu"

    For IPv4 connected device(s) use:

        set myTld="ipv4.pool.chrony.eu"

    For and IPv6 connected device(s) use:

        set myTld="ipv6.pool.chrony.eu"

8.) Configure NTP client.

Continue with this list of commands to configure Windoes NTP client:

   set myServers="1.%myTld%,0x08 2.%myTld%,0x08 3.%myTld%,0x08 4.%myTld%,0x08"
   set myKey=HKLM\SYSTEM\CurrentControlSet\Services\W32Time\Parameters
   REG QUERY %myKey%
   w32tm /config /manualpeerlist:%myServers% /syncfromflags:manual /update
   REG QUERY %myKey%

Description of operation

This procedure will enable NTP client, set minimum update interval to 64s (1min 4sec), maximum update interval to 1024s (17min 3sec) and configure NTP client depending on computer connectivity. Correction of MinPollInterval and MaxPollInterval is necessary because default values are too coarse for built in CMOS clock, which may have time drift of several seconds for default MaxPollInterval configured of 32768s (9hours 6minutes 8seconds). NTP client will slowly drift time in computer to correct NTP synchronized time. How long will computer run synchronization is dependent from current skew from correct time.

Synchronization of computer time is maintained until computer is powered on. Depending on duration of power off time, internal CMOS clock maintains coarse time. At computer power on event NTP client reads configuration and starts with time synchronization. If time difference between computer and reference source is reasonably small, time is adjusted in several steps and time synchronization is achieved quickly. For long power off periods, when there is sufficient time difference between CMOS battery time and reference source synchronization time may be reasonably long.