Recently, Microsoft released an update to Windows Server 2012 R2 which – next to a bunch of bug fixes – also includes new features to some of the Operating System’s components. Amongst these new features there’s one that I found particularly interesting, more specifically the update to the AD FS 3.0 component which enables customers to use a different attribute to identify federated uses in Windows Azure AD. The feature itself is better known as “Alternate Login ID”.
As the TechNet documentation on this topic describes, it would now be possible to use a different attributed from the User Principal Name to identify federated users in Office 365. This helps customers who aren’t able to change their UPNs from the current value (like e.g. domain.local or domain.corp) to an internet-routable domain (like domain.com). Even though that in many situations changing the UPN isn’t a big of a deal, some customers leverage the existing UPN in third party applications and therefore might not be able to make this change easily.
If you want to deploy this feature, you’ll have to figure some things out by yourself. The documentation that is currently available doesn’t explain all the steps. At least, that is if you want to implement it right away. I expect the documentation to become available shortly. Also mind that I haven’t seen any official statement that the use of “Alternate Login ID” is already supported by Office 365 today, but the documentation certainly hints to it and if I recall correctly, it was also announced at the Microsoft Exchange Conference, last week.
The configuration itself requires you to jump through a few hoops, including modifying DirSync to refer to the new attribute you’ve selected as being the Alternate Login ID instead of the UPN. Personally, I would still recommend changing the UPN – if possible. But there’s an alternative now and having alternative is always good thing, isn’t it?
I’ll definitely have a go at this later this week and will post my findings here.
[Update 04/14/2014] Here’s the KB article describing the update I reference in this article: http://support.microsoft.com/kb/2927690