Messaging Gateway

Hi, I have a SMG in my network border and an Exchange 2013 on-premise server. The SMG is configured to send mail accepting them from the Exchange and to route emails to the Exchange. We are recently facing a lot of smtp authentication tentatives from outside and I'd like to protect my internal domain from attacks. I see that Directory Integration is enabled, and LDAP server is configured and the only feature enabled is Authentication. The question is: do I need this feature to be active for receiving and sending emails from/to my internal exchange? I really can't understand if this feature only let users authenticate directly on the appliance, and if yes, I don't need it since my users send emails from outlook connected to exchange, the SMG only sends and receive emails from/to it. I have no CAS or other appliances and I have local users to login into the control panel.

Thank you

The LDAP Authenitcation feature lets users log in to the Messaging Gateway to check their spam quarantine. Newer versions of the Messaging Gateway also let you set up administrators to be able to log in with their AD credentials.

This feature is not required to deliver to your Exchange server. SMTP Auth only work for outbound emails and allows users to bypass your Exchange server when they are not on-premise (remote) and send outbound emails directly from the SMG.