Yet another drop-in Sendmail replacement is qmail. Like Postfix, qmail was designed to be secure, to perform well, to be reliable, and simple. Designed by Dan Bernstein (author of djbdns), and first released in 1997, it also follows the Unix tradition of using small, simple programs to accomplish small tasks and linking these programs together to perform more complex tasks. However, much like the http://cr.yp.to/qmail.html and http://www.qmail.org/ web sites, the software is "not designed to be easy to use," writes Russell Nelson on the (unofficial) qmail home page (August 13, 2004, http://www.qmail.org/). Qmail implements exceptionally fast and secure MTA functionality, but was designed to be different from most other mailers. If you are primarily familiar with Sendmail or Postfix but do not yet have experience with qmail, you will be at a disadvantage when trying to effectively deploy and administer a server running qmail. In this chapter, we focus on Sendmail and Postfix because their similarities allow us to address security concerns instead of the mail software itself. If you are deploying a mail server running qmail on OpenBSD or FreeBSD, you are likely to find the information in this chapter generally useful but not specific to your situation. Also consider resources such as the qmail web sites mentioned above, http://www.lifewithqmail.org/, and the O'Reilly book qmail by John Levine. |