Office 365 - Shared MailBoxes

Shared MailBoxes allow multiple users to view and send email messages from a common mailbox.

Creating Shared MailBox from Admin Center

1. Go to Exchange Admin Center
   
   
   1. From Office 365 Admin Portal (https://portal.office.com/adminportal/home#/homepage ), click on Admin Centers >> Exchange.
   2. We will be redirected to the Exchange Admin Center (https://outlook.office365.com/ecp/?rfr=Admin_o365&exsvurl=1&mkt=en-US&Realm=<mydomain>.onmicrosoft.com )
   3. Click on “Recipients” and then Shared, we will be redirected to the page where we can View / Edit / Delete and create new, shared mailboxes.
   4. On the tool bar shown as in the following figure, click on plus (+) sign.
   5. “New Shared Mailbox” will open as shown below.
      
      
      Figure 1: Office 365 - Shared MailBox - New Shared MailBox dialog
      
      
   6. In “New Shared Mailbox” dialog, we need to provide “Display Name”, “Email address” and then we need to add the users. Under “More Options”, specify “Alias:” for shared mailbox

Creating Shared MailBox from PowerShell

We can create new shared mailbox using New-Mailbox PowerShell cmdlet

PS C:\> New-Mailbox -Shared -Name "TestSharedMailBox" -DisplayName "Test Shared MailBox" -Alias TestSharedMailBox

If we run the above command from “SharePoint Online Management Shell” or “Windows PowerShell”, this command will run from these consoles only if there is no “Multi Factor Authentication” is not enabled. If we enable “Multi Factor Authentication” then we need to use “Exchange Online Remote PowerShell Module” and we need to use the Connect-EXOPSSession cmdlet to connect.

Few points regarding Shared MailBoxes

1. Shared MailBox allows users to have common calendar.
2. Storage Quota for Shared MailBox is 50 GB. Until 50 GB, no licenses were needed to be assigned. Once the Storage Quota exceeds 50 GB, Shared Mailbox will be locked.
3. To access a Shared MailBox, user must have Exchange Online license.
4. If we want to enable “In-Place Archive” or “put an In-Place Hold or Litigation Hold” on Shared MailBox, then an “Exchange Online Plan 2” or an “Exchange Online Plan 1 with Exchange Online Archiving license” is required.
5. If we enable In-Place Archive or auto-expanding archiving 100 GB storage is automatically added for Shared MailBox
6. Shared MailBox doesn’t require username and password. User needs to sign in with his or her own account and then open the shared mailbox
7. Users needs to be granted permission on Shared MailBox.
8. Following are the permissions used on Shared MailBox.
   
   
   1. Full Access
      
      1. When “Full Access” permission is granted to user on Shared MailBox, user acts as owner of the mailbox
      2. But to send email from Shared MailBox, user needs to assign additional permissions otherwise these users can’t send email from Shared MailBox
      3. User with these permissions, is able to create calendar items, read / view / delete email messages
         
         
   2. Send As
      
   1. When “Send As” permissions are granted to user on Shared MailBox, users can send the mail as the shared mailbox.
      
      
   3. Send on Behalf
      
   1. When “Send on Behalf” permissions are granted to user on Shared MailBox, user can send mail on behalf of the Shared MailBox.

References

• https://blogs.technet.microsoft.com/lystavlen/2011/11/04/understanding-shared-mailboxes-in-office-365-updated/ - This is very old reference, now things changed bit but small blog worth to read once.
• https://technet.microsoft.com/en-us/library/exchange-online-limits.aspx#StorageLimits

Thanks for reading.