How to Configure “Send on Behalf” Permissions on a Shared Mailbox in Exchange Online

In the Exchange Online environment, it is often necessary for multiple users to manage emails from a shared mailbox. One of the most useful functions is the ability to send emails on behalf of another person or shared mailbox. This is achieved by setting the appropriate permissions. In this article, we will explore how to use the `Set-Mailbox` command to assign “Send on Behalf” permissions to a shared mailbox.

 What is “Send on Behalf”?

The “Send on Behalf” function allows a user to send emails on behalf of another email account. The recipient of the email will see something like “Sent by user@xyz.com on behalf of sharedmailbox@xyz.com.” This is especially useful in collaborative environments where multiple users need to represent a specific mailbox.

Using the `Set-Mailbox` Command

To grant a user “Send on Behalf” permission for a shared mailbox, we use the `Set-Mailbox` command in PowerShell. Below is the command and its syntax:

“`powershell
Set-Mailbox -Identity sharedmailbox@xyz.com -GrantSendOnBehalfTo @{add=”user@xyz.com”}
“`

Command Breakdown

• `Set-Mailbox`**: This cmdlet is used to modify the properties of a mailbox.
• `-Identity`**: Specifies the mailbox you want to modify. In this case, it is `sharedmailbox@xyz.com`.
• `-GrantSendOnBehalfTo`**: This parameter is used to add, remove, or replace users who have the “Send on Behalf” permission.
• `@{add=”user@xyz.com”}`**: This is a hash table specifying the user being granted the permission. The `add` action adds the specified user to the list of users with “Send on Behalf” permission.

 Steps to Configure the Permission

1. **Open PowerShell**: Log in to your PowerShell environment and connect to Exchange Online.

“`powershell
$UserCredential = Get-Credential
Connect-ExchangeOnline -UserPrincipalName user@xyz.com -ShowProgress $true -Credential $UserCredential
“`

2. **Run the Command**: Once connected to Exchange Online, run the following command to grant the “Send on Behalf” permission:

“`powershell
Set-Mailbox -Identity sharedmailbox@xyz.com -GrantSendOnBehalfTo @{add=”user@xyz.com”}
“`

3. **Confirmation**: No need to restart any services. The permission is applied immediately, and `user@xyz.com` will be able to send emails on behalf of `sharedmailbox@xyz.com`.

Verification

To ensure the permission has been configured correctly, you can verify it using the following command:

“`powershell
Get-Mailbox -Identity sharedmailbox@xyz.com | Select-Object -ExpandProperty GrantSendOnBehalfTo
“`

This command will display all users who have the “Send on Behalf” permission for the specified mailbox.