Exchange 2013 data loss prevention is a feature that allows manual enforcement of message content rules in Exchange to ensure that specific content is not accessible to unauthorized parties.
Exchange 2013 DLP uses message templates to block or filter sensitive data that is found in most enterprise IT environments. By controlling what flows in and out of an Exchange Server 2013 organization, an administrator can meet business rules for privacy and compliance.
Administrators can use existing DLP message policy templates, build on top of existing templates and create templates from scratch with tools in the Exchange Administration Center. Templates may be tested without being placed into production to test policy templates without affecting mail flow.