Book Image

SpamAssassin: A practical guide to integration and configuration

Book Image

SpamAssassin: A practical guide to integration and configuration

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.
Table of Contents (24 chapters)
SpamAssassin
Credits
About the Author
About the Reviewers
Introduction
Glossary

How Spammers Verify Email Addresses


Spammers can verify email addresses in three ways: by receiving replies, providing an opt-out web link, and by using web bugs. Web bugs are small images that secretly track information about the spam recipient. The following section describes a web bug in detail. A recipient of spam may occasionally reply to a spammer's email. This is a futile gesture. Often, the spam email is sent from a fictional email address, and the reply will be returned, undelivered. Spam can also be sent from a real, but hijacked address. Hijacking occurs when the spammer chooses a bona-fide email address to use in the mail headers of his or her spam, either the From: header or the Reply-To: header. The unfortunate victim will receive thousands of bounced messages from undelivered emails, as well as the occasional irate reply.

Note

One golden rule about spam is never to reply and never to click an opt-out link.

Email is occasionally sent from an account set up by the spammer. If...