Do we need extra licenses Microsoft Defender for Office 365 (Plan 1) for shared mailboxes?

Question

Hello.

I would like to confirm that I understand correctly the licensing regarding standard mailboxes for users and shared ones. Microsoft Defender for Office 365 service description.

We have 55 users and 10 shared mailboxes that some of the users have together.
We have 55 licenses for Microsoft 365 Business Standard and 55 licenses Microsoft Defender for Office 365 (Plan 1). One of each for every user.

My understanding is that if the standard user has the Microsoft Defender for Office 365 (Plan 1) license then the shared mailbox does benefit. The only catch is that every user has to have the Microsoft Defender for Office 365 (Plan 1) license otherwise even if one doesn't have it the share mailbox won't be protected.

Or I'm mistaken and we need +10 licenses of Microsoft Defender for Office 365 (Plan 1) for the shared mailboxes?

Kind regards.

Answer 1

Hi,@Dimitris P Kepenos

Thanks for posting your question in the Microsoft Q&A forum.

If all users that have access to the shared mailboxes have a Microsoft Defender for Office 365 license, then the shared mailboxes will be automatically protected.

This means if all 55 of your users have a license for Microsoft Defender for Office 365 Plan 1, and these users are the ones accessing the 10 shared mailboxes, then the shared mailboxes should be protected without requiring additional licenses specifically for the mailboxes.

However, if you were to have a user without Defender for Office 365 who needs to access a shared mailbox, that mailbox would not be protected by Defender features until that user is also licensed.

You can refer to this link for details:https://learn.microsoft.com/en-us/office365/servicedescriptions/office-365-advanced-threat-protection-service-description?source=recommendations#licensing-terms

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