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Chapter 18; Choosing other Spam Tools

SpamAssassin is the Swiss-army knife of spam filtering. By encompassing other technologies such as DCC and RBLs, coupled with highly configurable rules-based scoring, it holds an edge over most alternative spam filters.

However, there may be benefits to using more than one spam-filtering tool:

• If system load on an email server is high, a separate machine hosting a simple filter can filter out obvious spam, allowing further filtering to be carried out using SpamAssassin. ISPs often take this approach, filtering some spam, notably pornographic spam and verbatim copies of known spam, but avoiding statistical analysis, which is computationally intensive.

• A spam filter that uses a different statistical analysis method than SpamAssassin will be triggered by different spam. This should produce a higher combined filtering rate.

• By using two filters, spam detection policies become more flexible. At the simplest level, emails can be considered spam if and only if both filters mark the emails are spam. Alternatively, email can be considered spam if at least one filter detects spam.

• If two filters are in place, SpamAssassin thresholds can be modified to reduce false negatives or false positives.
   

• Chapter 18: Table of Contents:

  • Spam Policies

  • Evaluating Spam Filters

  • Configuring the Second Filter

    • Using a Single Machine

    • Using Separate Machines

      • Sendmail

      • Postfix

      • Exim

      • qmail

  • Other Techniques

    • Greylisting

    • SPF

    • Sender Validation

  • Summary

BOOK DETAILS   Paperback, 220 pages Released: Sept 2004 ISBN: 1904811124 Author: Alistair McDonald

TABLE OF CONTENTS

Intro
1. Introducing Spam
2. Spam and Anti-Spam Techniques
3. Open Relays
4. Protecting Email Addresses
5. Detecting Spam
6. Installing SpamAssassin
7. Configuration Files
8. Using SpamAssassin
9. Bayesian Filtering
10. Look and Feel
11. Network Tests
12. Rules
13. Improving Filtering
14. Performance
15. Housekeeping and Reporting
16. Building an Anti-Spam Gateway
17. Email Clients
18. Choosing other Spam Tools
Appendix A
Index
 

View the book details on PacktPub.com