Network Tests | SpamAssassin: A practical guide to integration and configuration

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SpamAssassin: A practical guide to integration and configuration

4 (4)

SpamAssassin: A practical guide to integration and configuration

4 (4)

Overview of this book

As a busy administrator, you know Spam is a major distraction in todays network. The effects range from inappropriate content arriving in the mailboxes up to contact email addresses placed on a website being deluged with unsolicited mail, causing valid enquiries and sales leads to be lost and wasting employee time. The perception of the problem of spam is as big as the reality. In response to the growing problem of spam, a number of free and commercial applications and services have been developed to help network administrators and email users combat spam. Its up to you to choose and then get the most out of an antispam solution. Free to use, flexible, and effective, SpamAssassin has become the most popular open source antispam application. Its unique combination of power and flexibility make it the right choice. This book will now help you set up and optimize SpamAssassin for your network.

SpamAssassin

SpamAssassin

Credits

Credits

About the Author

About the Author

About the Reviewers

About the Reviewers

Introduction

Introduction

Free Chapter

Introducing Spam

Introducing Spam

Defining Spam

The Costs of Spam

Spam and the Law

Summary

Spam and Anti-Spam Techniques

Spam and Anti-Spam Techniques

Spamming Techniques

Anti-Spam Techniques

Spam Filtering Services

Anti-Spam Tools

Summary

Open Relays

Open Relays

Email Delivery

Open Relay Tests

MTA Configuration

Summary

Protecting Email Addresses

Protecting Email Addresses

Websites

Usenet

Trojan Software

Mailing Lists and Archives

Registration for Websites

Employees

Business Cards and Promotional Material

How Spammers Verify Email Addresses

Summary

Detecting Spam

Detecting Spam

Content Tests

Header Tests

DNS-Based Blacklists

Statistical Tests

Message Recognition

URL Recognition

Examining Headers

Reporting Spammers

Valid Bulk Email Delivery

Summary

Installing SpamAssassin

Installing SpamAssassin

Building from Source

Using CPAN

Installing by Hand

Resolving Build Failures

Packaged Distributions

Verifying the Installation

Upgrading

Uninstalling

SpamAssassin Components

Summary

Configuration Files

Configuration Files

Configuration Files

Rule Files

Summary

Using SpamAssassin

Using SpamAssassin

SpamAssassin as a Daemon

SpamAssassin and Procmail

Integrating SpamAssassin into the MTA

Testing and Troubleshooting

Rejecting Spam

Summary

Bayesian Filtering

Bayesian Filtering

Scoring

Training

Confirming Operation

Filter Training

Disabling Bayesian Filtering

Summary

Look and Feel

Look and Feel

Headers

Reports

Subject Rewriting

Summary

Network Tests

Network Tests

RBLs

SURBLs

Vipul's Razor

Pyzor

DCC

Spamtraps

Summary

Rules

Rules

Writing Rules

Using Other Rulesets

Summary

Improving Filtering

Improving Filtering

Whitelists and Blacklists

The Auto-Whitelist

Resolving Incorrect Classifications

Character Sets and Languages

Summary

Performance

Performance

Bottlenecks

Performance Improvement Methodology

Using SQL

Summary

Housekeeping and Reporting

Housekeeping and Reporting

Separating Levels of Spam

Detecting When SpamAssassin Fails

Spam and Ham Reports

Summary

Building an Anti-Spam Gateway

Building an Anti-Spam Gateway

Choosing a PC Platform

Choosing a Linux Distribution

Configuring Postfix

Installing Amavisd-new

Configuring Amavisd-new

Configuring Postfix to Run Amavisd-new

Configuring External Services

Firewall Configuration

Backups

Testing

Going Live

Summary

Email Clients

Email Clients

General Configuration Rules

Microsoft Outlook

Microsoft Outlook Express

Mozilla Thunderbird

Qualcomm Eudora

Summary

Choosing Other Spam Tools

Choosing Other Spam Tools

Spam Policies

Evaluating Spam Filters

Configuring the Second Filter

Other Techniques

Summary

Glossary

Glossary

Chapter 11. Network Tests

SpamAssassin on its own can detect a high proportion of spam. By using network tests, spam detection can be further improved. SpamAssassin includes support for Realtime BlockLists (RBLs) and Spam URI Realtime BlockLists (SURBLs). All these external services are easy to integrate into SpamAssassin.

The effectiveness of network tests varies from a 60% detection rate upwards. By using them in conjunction with SpamAssassin, spam detection rates are much higher, typically over 95%! However, network tests slow down spam detection. This means that the SpamAssassin processes will take longer to complete and will increase the memory usage of the email server.

This chapter describes the support SpamAssassin has for RBLs and SURBLs, and focuses on three external services:

Vipul's Razor
Pyzor
The Distributed Checksum Clearinghouse (DCC)

RBLs are blocklists of known sources of spam. By default, SpamAssassin uses a number of RBLs to check the source of the email.

A SURBL is a blocklist...

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Tech Concepts

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Programming languages

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