In a company using the exchange / outlook combination is there any way to block users from using outlook to receive non-exchange mail? We are concerned about people adding their personal email to the Outlook accounts and subsequently being exposed to more viruses. The mail that goes through exchange is guaranteed to be scanned before it's viewed. I know that POP3 and SMTP can be blocked by ports, but what about services like HOTMAIL where outlook can use HTTP to retrieve mail? Is the only solution to block that site (making it so users can't see any hotmail pages in the browser either)?
Thanks, -tim