<p>In our environment with two Active Directory forests, we had to configure PDC&#8217;s from one domain to use PDC from another domain as a time source. I have tried to use the following command to set the time source for the PDC:</p>
<p><strong>w32tm /config /manualpeerlist:</strong><em>timeserver</em><strong> /syncfromflags:manual /reliable:yes /update</strong></p>
<p>Where the <em>timeserver</em> is the FQDN or IP address of the PDC server from another forest/domain.</p>
<p>I have also tried to follow several tutorials from <a href="https://support.microsoft.com/en-us/help/816042/how-to-configure-an-authoritative-time-server-in-windows-server" target="_blank" rel="noopener noreferrer">Microsoft</a> and from <a href="https://www.experts-exchange.com/questions/28575798/Computers-in-domain-time-source-Free-running-system-clock-How-to-correct-this.html" target="_blank" rel="noopener noreferrer">other forums</a> on the web. Unfortunately, time on PDC&#8217;s in the second domain was out of synch. After I haven&#8217;t managed to set up the time sync, I decided to try with the GPO.</p>
<p>I have edited Default Domain Controllers policy to configure the time server from another domain. After this, the time between two domain was in sync.</p>
<p>Open Group policy editor and edit the <strong>Default Domain Controllers policy</strong>.</p>
<p>Navigate to: <strong>Administrative Templates &#8211; System &#8211; Windows Time Service &#8211; Time Providers</strong></p>
<p>In the right pane, select Configure Windows NTP Client and set it in the following way.</p>
<p>Ntp Server: <strong>%FQDN of NTP server%,0x9</strong><br />
Type: NTP<br />
CrossSiteSyncFlags: <strong>2</strong><br />
ResolvePeerBackoffMinutes: <strong>15</strong><br />
ResolvePeerBackoffMaxTimes: <strong>7</strong><br />
SpecialPollInterval: <strong>3600</strong><br />
EvenLogFlags: <strong>0</strong></p>
<p>Please change the <strong>%FQDN of NTP server%</strong><strong> </strong>with your server name.</p>
<p><img class="alignnone size-full wp-image-3152" src="https://www.wincert.net/wp-content/uploads/2019/06/ntp-server-1.png" alt="" width="468" height="532" /></p>
<p><img class="alignnone size-full wp-image-3153" src="https://www.wincert.net/wp-content/uploads/2019/06/ntp-server-2.png" alt="" width="751" height="472" /></p>
<p>After the policy has been set, on the domain controller please run the following command:</p>
<p><strong>gpupdate /force</strong><br />
<strong>W32tm /resync /rediscover</strong></p>
<p>Once this is done, your DC should be synced.</p>

How to configure time source (NTP server) for a PDC
