Steps to link Existing domain with ADSelfService Plus
Go to Configuration --> Self-Service --> Password Synchronizer.
Click Active Directory. You will be presented with Active Directory configuration page.
Select the domain name to which password to be synced.
Enter a brief description of the configuration.
Select the Policies from policies drop-down box. Password Synchronization will be possible for only those users who fall under the selected self-service policies.
Important: For domain name, select the domain to which the passwords need to be synced. For example, if you want to sync passwords from Domain A to Domain B, then select Domain B in the Domain Name field and select a self-service policy associated with Domain A in the Associate Policies drop down list.