How to rule shared mailbox to not resend mail

When you have a shared mailbox, it's common to want to prevent duplicate emails from being sent to the same recipients. Here are a few ways to achieve this:

Method 1: Use a Transport Rule

1. Go to the Exchange admin center (EAC) and navigate to Mail flow > Rules.
2. Click New rule and select Apply to all messages.
3. In the Conditions section, select The sender is and choose the shared mailbox.
4. In the Actions section, select Modify the message and choose Delete the message.
5. Click Save to apply the rule.

This rule will delete any emails sent from the shared mailbox, preventing them from being resent.

Method 2: Use a Journaling rule

1. Go to the EAC and navigate to Mail flow > Journaling.
2. Click New journal rule and select Apply to all messages.
3. In the Conditions section, select The sender is and choose the shared mailbox.
4. In the Actions section, select Journal the message.
5. Click Save to apply the rule.

This rule will journal (log) any emails sent from the shared mailbox, but not delete them. You can then use the journaling logs to identify and prevent duplicate emails.

Method 3: Use a third-party add-in

There are several third-party add-ins available that can help you prevent duplicate emails from being sent from a shared mailbox. Some popular options include:

• SaneBlackHole: A free add-in that can be configured to delete or journal emails sent from a shared mailbox.
• Duplicate Email Remover: A paid add-in that can be configured to remove duplicate emails from a shared mailbox.

Method 4: Use a script

You can also use a PowerShell script to achieve this. Here's an example script that deletes emails sent from a shared mailbox:

$sharedMailbox = "[email protected]"
$deleteAfter = 1 # delete emails after 1 minute

Get-Mailbox -Identity $sharedMailbox | Get-MailboxFolder -Identity "Inbox" | Get-Item | ForEach-Object {
    $email = $_.GetItem()
    $email.Delete($deleteAfter)
}

This script deletes emails from the shared mailbox's inbox after a specified time period (in this case, 1 minute).

Remember to test each method thoroughly to ensure it works as expected and doesn't cause any unintended consequences.