1. Compile a list of the Exchange and edge MTA IP Addresses
  2. Within the edge MTA settings update the Allow Relay and add in the new DLP Email Prevent IP Addresses
  3. Within the DLP Email Prevent configuration make sure to setup the forward address to the MTA IP Address, add in the allow relay to only allow Exchange to send to Email Prevent, and validate the port to accept and relay are correct (25 is most cases)
  4. On Exchange create a new send connector to point to a test domain in which a test email address is hosted. Example the send connector could be for gmail.com and all email sent to Gmail would go through Email Prevent