This article, first by e-mail on the harmful impact of the unit, analyzes the Qmail mail system used by security problems, and can set the security policy studies, through the mail system security policy on the actual improvements to enhance the message of this unit System resilience of the harmful messages to ensure the safety of users e-mail. In the main text of the current of the more common e-mail security policy analysis and research unit for my actual e-mail by setting appropriate security policies, improve the unit’s e-mail security.