When you create an exchange mailbox for a user there are 3 protocols enabled by default:

  • OWA
    • web-based version of the Outlook email program;
    • direct live connection to the mail server;
    • shared Calendar, Contacts, Tasks, Notes and free/busy information for scheduling; public folders;
    • Out of Office Assistant;
    • Server-side rules and alerts;
    • Optional server-side spam management;
  • IMAP - direct live connection to the mail server
  • POP - send/receive mail only

You can find and manage these protocols under CONTROL PANEL > Services > Mailboxes > Exchange Mailboxes > select a mailbox > Advanced settings 

Advanced Settings

Note: even if all protocols are disabled under Advanced settings Outlook desktop application still can be configured for an Exchange mailbox using MAPI protocol.