Block Outbound Emails for a Group of Users

Request was to block all Exchange Admins accounts from sending out external emails.

 

This can be done easily with a Transport Rule:

 

Create a Distribution Group and add all the Exchange Admin accounts that you want to block: ExAdmins@e2k10.local

 

Start the New Transport Rule Wizard

Give the New Transport Rule a Name: "Block Exchange Admins External Email

 

For the Conditions select "From a member of distribution list"

 

Select the Distribution Group you just created for the ExAdmins

 

 

Also under Conditions select:

"from users that are inside or outside the organization" - Inside the Organization

"sent to users that are inside or outside the organization" - Outside the Organization

 

For Actions select "send rejection message to sender with enhanced status code"

Message: External Email Blocked

Status code: 5.7.1

 

Complete the wizard and create the rule

 

If you don't want to use the New Transport Rule wizard you can just edit and run the following command:

 

New-TransportRule -Name 'Block Exchange Admins External Email' -Comments '' -Priority '0' -Enabled $true -FromMemberOf 'ExAdmins@e2k10.local' -FromScope InOrganization -SentToScope 'NotInOrganization' -RejectMessageReasonText 'External Email Blocked' -RejectMessageEnhancedStatusCode '5.7.1'