Product Description : The Book of Postfix: State-of-the-Art Message Transport Best practices for Postfixthe popular alternative to SendmailDeveloped with security and speed in mind Postfix has become a popular alternative to Sendmail and comes preinstalled in many Linux distributions as the default mailer The Book of Postfix is a complete guide to Postfix whether used at home as a mailrelay or virusscanning gateway or as a company mailserver Practical examples show how to deal with daily challenges like protecting mail users from spam and viruses managing multiple domains and offering roaming access ( it is an used product )