Want to start a conversation with a stranger? Ask about the most outrageous spam message he or she has ever received. Because everyone who has an email account gets spam, this icebreaker is almost guaranteed to work—although the answer you get might embarrass one or both of you!
Many Exchange administrators use third-party mail filters, but Exchange Server
2003 has a surprisingly good set of built-in spam-reduction tools. In fact,
Microsoft uses these tools as a first line of defense for its own systems, and
Microsoft employees will generally tell you that they don't get much spam. Is
your organization getting the most out of Exchange 2003's built-in tools? To
answer that question, you need a thorough understanding of the tools, how they're
applied, and your configuration options.
The Exchange Antispam Process
Exchange 2003 incorporates several types of antispam protection, including blocking
mail from specific IP addresses or senders and filtering with the Microsoft
Exchange Intelligent Message Filter (IMF). Exchange applies filtering techniques
in a predictable-sequence. The process starts when a remote system opens an
SMTP connection to the Exchange server. If the server is accepting connections,
the following types of filtering take place:
- Connection filtering—Exchange applies checks based on the sender's
IP address and other data, such as whether the SMTP conversation has the correct
syntax.
- Sender and recipient filtering—Exchange checks for the sender's IP
address on any blacklists and checks the sender and recipient addresses against
its lists of permitted users and blocked users.
- Content filtering—Exchange passes the message through the IMF (if
it's enabled).
Exchange then submits the message to the mailbox store, where it may be acted upon by the store (according to options set in the IMF) or by the client-side Outlook junk mail filter. . . .

