Add User Principal Name Suffixes
Applies To: Windows Server 2008, Windows Server 2008 R2, Windows Server 2012
You can use Active Directory Domains and Trusts to add user principal name (UPN) suffixes for the existing user account. The default UPN suffix for a user account is the Domain Name System (DNS) domain name of the domain that contains the user account. You can add alternative UPN suffixes to simplify administration and user logon processes by providing a single UPN suffix for all users. The UPN suffix is used only within the Active Directory forest, and it is not required to be a valid DNS domain name.
Membership in Domain Admins or Enterprise Admins , or equivalent, is the minimum required to complete this procedure. Review details about using the appropriate accounts and group memberships at https://go.microsoft.com/fwlink/?LinkId=83477.
To add UPN suffixes
Open Active Directory Domains and Trusts. To open Active Directory Domains and Trusts, click Start , click Administrative Tools , and then click Active Directory Domains and Trusts .
In the console tree, right-click Active Directory Domains and Trusts , and then click Properties .
On the UPN Suffixes tab, type an alternative UPN suffix for the forest, and then click Add .
Repeat step 3 to add additional alternative UPN suffixes.
Additional considerations
To perform this procedure, you must be a member of the Domain Admins group or Enterprise Admins group in Active Directory Domain Services (AD DS), or you must have been delegated the appropriate authority. As a security best practice, consider using Run as to perform this procedure. For more information, search for "using run as" in Help and Support.
UPN suffixes should conform to DNS conventions for valid characters and syntax.
You can also perform the task in this procedure by using the Active Directory module for Windows PowerShell. To open the Active Directory module, click Start , click Administrative Tools , and then click Active Directory Module for Windows PowerShell . For more information about Windows PowerShell, see Windows PowerShell (https://go.microsoft.com/fwlink/?LinkID=102372).