Table of contentsPractical Methods for Combating Spam
AOL reports it blocks approximately 1 billion spam e-mails per day
Agenda for Today
How Internet E-Mail Works
Slide 5
SMTP suffers from the following shortcomings…
How Spammers Exploit Internet E-Mail
A Few Years Ago: Open Relays
More Recently: Cheap Broadband
Tools to Fight Spam
Blacklists and Whitelists
Distributed 'Bulk-Measurement' Tools
Problems with Distributed 'Bulk-Measurement' Tools
Distributed Spam-Reporting Centers
Problems with Distributed Spam-Reporting Centers
Sender-Verification Tools
Problems with Sender-Verification Tools
Content Filters
Problems with Content Filters
Bayesian Content Filters
Problems with Bayesian Content Filters
Best Option
False Positives
Profile of the Ideal Anti-Spam Tool
SpamAssassin and MIMEDefang
SpamAssassin
SpamAssassin (CONT.)
Calling SpamAssassin
Examples of Rules
Check for Sender/Relay Mismatches
Force a Retry
Force a Retry (Cont.)
Check the HELO string
Use Open-Relay Blacklists
Examples of Other Rules
Summary
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