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📖 What is Exchange Online Mailbox Delegation?

Exchange Online Mailbox Delegation allows a user to grant another user permission to access their mailbox. Common types include 'Send As,' 'Send on Behalf of,' and 'Full Access,' enabling assistants or managers to manage emails without sharing account passwords.

🥋 Sensei Says:

"'Send As' makes the email appear to come directly from the owner, while 'Send on Behalf of' explicitly states who sent it."

📚 Certification: Microsoft 365 Administrator (MS-102)

🔑 What are the Key Concepts of Exchange Online Mailbox Delegation?

  • Full Access permission allows a delegate to open and manage a mailbox, including reading and deleting emails, but does not permit sending messages.
  • Send As permission allows a user to send emails that appear to originate directly from the mailbox owner, hiding the delegate's identity from recipients.
  • Send on Behalf of permission allows a delegate to send mail, but the recipient sees that the message was sent by the delegate for the owner.
  • Automapping is a feature where mailboxes granted Full Access are automatically added to the delegate's Outlook client without requiring manual configuration.
  • Mailbox delegation enhances organizational security by eliminating the need to share account passwords, ensuring access is managed through official administrative permissions.

🎯 How does Exchange Online Mailbox Delegation appear on the MS-102 Exam?

You may be asked to determine which permission to assign to an executive assistant who must send emails that appear to come directly from the CEO.

A scenario might describe a user who can read an owner's emails but receives a permission error when trying to send a reply from that mailbox.

Expect questions about the difference between 'Send As' and 'Send on Behalf of' when a company requires transparency regarding who actually authored a message.

❓ Frequently Asked Questions

Does granting Full Access automatically allow a user to send emails from that mailbox?

No, Full Access only grants permission to open and manage the mailbox contents. To send emails, you must separately assign either 'Send As' or 'Send on Behalf of' permissions.


What happens if Automapping is disabled when granting Full Access?

The delegate will still have permission to access the mailbox, but they must manually add the shared or delegated mailbox to their Outlook profile via account settings.

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