The automatic domain join feature has several requirements.

During the customization process, for Windows 2000, Microsoft Sysprep attempts to join the domain before network customization occurs. Therefore, the network properties of the source virtual machine are used to attempt to join the domain.

If the source virtual machine network properties are such that the domain controller is not resolvable, domain join fails.

If the source virtual machine was configured with a manually configured DNS, that DNS is contacted to resolve the domain controller even if the manually configured DNS is not on the network. In the case where the DNS cannot be found, domain join fails.

If the source Windows 2000 virtual machine was configured with DHCP, the new network DHCP is used to attempt to resolve the domain controller. In this case, if the DNS that is configured to the DHCP can resolve the domain controller, domain join succeeds.

During customization for Microsoft Windows XP or later, Microsoft Sysprep resets the guest to configure the network settings to DHCP before attempting to join the domain, regardless of the source virtual machine or network settings. For automatic domain join to succeed, the DHCP on the network must be able to resolve the domain controller.