For example, if a DNS domain has four levels of child domains namely LEVEL3.LEVEL2.LEVEL1.LEVEL0.MYDOMAIN.COM, and a user account U-01 resides within the LEVEL3 domain, it would really become very complicated for the user have and use U-01@LEVEL3.LEVEL2.LEVEL1.LEVEL0.MYDOMAIN.COM while providing the credentials. Instead, it would be easier to have an alternate UPN suffix (such as ALLSUFF.COM) that can be substituted with the entire four level domain names. When an alternate UPN suffix is created, the user U-01 can simply use U-01@ALLSUFF.COM instead of typing the entire lengthy default UPN suffix.
In order to create an alternate UPN suffix in the domain, it is important that you log on to the target Windows Server 2012 domain controller with the Enterprise Admin or Domain Admin account credentials. If you do not use the said account credentials to log on, you will not be able to add the alternate UPN suffix to the domain whatsoever.
Here is how you can add alternate UPN suffix in Windows Server 2012 Active Directory domain controller:
- Log on to the Windows Server 2012 domain controller with the Enterprise Admin or Domain Admin account credentials.
- If not already started, initialize the Server Manager window from the bottom left corner of the screen.
- From the opened Server Manager window, go to Tools menu from the menu bar.
- From the displayed list, click Active Directory Domains and Trusts.
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- On the opened Active Directory Domains and Trusts snap-in, from the left pane, right-click
the Active Directory Domains and Trusts (<server name>). (DC-01.MYDOMAIN.COM for this demonstration.).
- From the displayed context menu, go to Properties.
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- On the opened properties box, in the Alternate UPN suffix field, type the new UPN suffix
that you want to add to the existing domain.
- Once done, click Add to add the new alternate UPN suffix to the list.
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- After adding, click OK to save the changes that you have made.
- Finally close the Active Directory Domains and Trusts snap-in.
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