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Qmail - a secure, fast, and reliable MTA

Qmail - "qmail is a secure, reliable, efficient, simple message transfer agent. It is designed for typical Internet-connected UNIX hosts."

Qmail doesn't do X! How can you use it?

Well, I do have to agree that the stock version of qmail is fairly limited. It works, but it creates many a nuisance to content with. Fortunately, Dan has made the code free. You can take it, hack it all up, and do pretty much anything you want with it, but once you change it, you can't call it qmail any more. Thus, the new "community" version of qmail is released as netqmail. On top of the netqmail distribution, we apply a patch that adds support for SMTP-AUTH, SSL/TLS encryption, regexp filtering, SPF, SpamThrottle, and email address validity checks.

Because qmail is so modular, it's easy to insert other programs into the email pipeline to add additional features, like virus and spam detection. See the filtering section for more details.

Where can I get more info about Qmail?

Here are a couple great resources: Life With Qmail & FAQTS - Qmail

The switch to Qmail

A long time ago (~1996) I owned an ISP. I was also the chief sysadmin and after spending another "unix day" in which I fought and cussed at sendmail after spending far too long hacking at a sendmail.cf file, I decided to give the "just releaesd" qmail a try. I installed it and two days later I had converted my email server cluster over to qmail. Although I occasionally glance towards Postfix, I have never looked back.

Taking it to the next level

In 2000 I was tasked to build an email solution to support 100,000 users. There were two competing virtual solutions for qmail (vpopmail & vmailmgr). I installed and tested both solutions and decided that vpopmail was where it was at and then set out to build the solution around it.

Since then, qmail has remained the faithful little MTA that could, faithfully powering several mega-clusters and the hundreds of email servers I have build since. It has never suffered a security vulnerability, it scales extremely well, and with a few patches to support additional anti-spam and virus features, it's an extremely robust foundation for Mail::Toaster.

The MTA's of the world

There are basically three MTA's in the world of note. Sendmail, Postfix, and Qmail. Sendmail used to be all that, but it's long history of security, difficult configuration, and scalability issues left many an administrator looking for an alternative.

At last, qmail came along providing an alternative. It was readily adopted by many and a vast assortment of software sprouted up along side it. Much of qmails attractiveness the fact that it's extremely simple, and designed to be extended by third party programs. The fact that it's never had a vulnerability is also nice.

At some point in the game, (long after I had switched to qmail) Postfix finally arrived under the guises of "vmailer". It is a good replacement for sendmail but I'm still waiting to see a great virtualized solution based around it. I do expect to see it at some point. Until then, I have qmail and vpopmail.

Last modified on 4/29/05.