Editing Domain controller (Windows) (section)

===PDC emulation (Primary Domain Controller)===
In modern releases of Windows, domains have been supplemented by the use of [[Active Directory]] services. In Active Directory domains, the concept of primary and secondary domain controller relationships no longer applies. PDC emulators hold the accounts databases and administrative tools. As a result, a heavy workload can slow the system down. The DNS service may be installed on a secondary emulator machine to relieve the workload on the PDC emulator. The same rules apply; only one PDC may exist on a domain, but multiple replication servers may still be used.<ref>{{Cite web|url=https://technet.microsoft.com/en-us/library/cc816793%28WS.10%29.aspx|title=Reducing the Workload on the PDC Emulator Master|publisher=Microsoft Technet 9 January 2009|accessdate=13 February 2011}}</ref>

* The PDC emulator master acts in place of the PDC if there are [[Windows NT 4.0]] domain controllers (BDCs) remaining within the domain, acting as a source for them to replicate from.
* The PDC emulator master receives preferential replication of password changes within the domain. As password changes take time to replicate across all the domain controllers in an Active Directory domain, the PDC emulator master receives notification of password changes immediately, and if a logon attempt fails at another domain controller, that domain controller will forward the logon request to the PDC emulator master before rejecting it.
* The PDC emulator master also serves as the machine to which all domain controllers in the domain will synchronise their clocks. It, in turn, should be configured to synchronise to an external [[Network Time Protocol|NTP]] time source.<ref>{{Cite web|url=https://technet.microsoft.com/en-us/library/cc794937%28WS.10%29.aspx|title=Configure the Time Source for the Forest|publisher=Microsoft Technet 9 January 2009|accessdate=13 February 2011}}</ref>