Accounts with same mail Attribute

Question

I have to search AD objects based on mail addresses (from/to/cc). Currently I try to search for all AD objects, with a mail property that matches an address :

(mail=[e-mail])

As result I have to expect an unique account to store its GUID. But it seems that mail isn't unique enough.

Under which circumstances is it possible, that 2 AD-Objects (different GUID) can have an identical mail attribute? And what's a best practice to map an MS-Exchange mailbox address to an AD-Object?

Answer 1

There are many reasons why you would have multiple AD Objects that would have the same email address. An easy one that comes to mind is any service accounts your company might have are probably not linked to their own email addresses but rather to individuals and/or to distribution lists. The same can apply to generic accounts such as "administrator" or test accounts.

Also, it is possible for users to have multiple accounts depending on your companies rules. Where I work we have a test domain where everyone has an admin and a regular user account, but both are mapped to the same email.

So basically depending on your organization's business logic and practices you many have one or many accounts with the same email.