qmail Information

2008-08-08 You may now select which stylesheet you want to use for this web site.

I started using qmail to handle email on my own server, and those of my employers, back in 1998. I have been very happy with it, and have yet to find any real cause for complaint. Every time I have found something I needed that it wouldn't or couldn't do, I found that either somebody had already written a patch to do what I needed, or I was able to write such a patch myself.

If you're not familiar with it, qmail is a mail transfer agent (MTA), or "mail server software". Unlike other MTAs like sendmail, which encapsulate all of their functions into one massive program, qmail is built as a collection of tiny programs, each of which does its one little piece of the puzzle, and does it well. This makes each individual program much easier to test and debug.

The official qmail web page is written and maintained by qmail's author, Dan Bernstein. Dr. Bernstein has written several other software packages, including daemontools, djbdns, and ucspi-tcp which are all very useful (especially on a machine running qmail.)

The un-official qmail.org site is written by other qmail "fans". This is where you will find a large collection of patches, as well as links to other information for people who are running, or thinking about running, qmail.

Life with qmail is a document which contains a fairly complete walk-through of installing qmail and configuring it for the first time. I hadn't seen this until after I had been running qmail for a few years, but the directions here are quite similar to how I have it set up. Very much recommended for people who are trying qmail for the first time and aren't used to it yet.

The big qmail picture is a set of diagrams (in GIF, PS, or PDF format) which show the various programs which make up qmail and how they relate to each other. These images were a major part of my own process of learning about how qmail works- in fact, at one of my former jobs (at an ISP) I printed out all four pages with a 36-inch plotter and hung them on the wall, just to refer to as needed.

Back in 2006, I made a few diagrams which are similar to the "qmail big picture", but which include programs outside of qmail that are commonly used with qmail (things like rblsmtpd, simscan, and so forth.) It used to be two separate diagrams, however I have since purchased a new version of OmniGraffle (yes, I pay for my software) and am now able to create multi-page diagrams, and export them as multi-page PDF files. I've also expanded the diagram to three pages:

1. Incoming: how mail gets into the queue, whether from a remote client or from a process on the local machine.
2. Outgoing: how mail gets out of the queue, whether it's going to a local mailbox or to a remote server.
3. Retrieval: how MUAs and most webmail systems access the messages stored in the mailboxes.

Note that this diagram is not meant as a deep reference, but as an overview to help you understand how the various programs "fit" with each other.

2008-04-25 I have recently started making regular use of the Subversion source code revision control system, with the Trac web front-end. This page on my regular web site explains how I set up the software. As an example, I have placed the "source code" of this web site under a repository, with a trac interface to look at changes over time.

Patches

I have moved this section to a page of its own because it was getting to be too long.

Scripts

I have also moved this section to a page of its own.

HOWTO pages

I have written a page which explains how to set up an SMTP service. This should be handy if you need multiple servers (i.e. one on port 25 for normal incoming mail, and an SSL-secured on port 465 to allow your users to AUTH and relay mail securely. I've also written a page on the options for TLS/SSL and AUTH, and a page on how to use the SMTP AUTH command when testing a server. It also shows how to use openssl to connect to an SMTP server which is using SSL or TLS to secure the connection.

I have written a page on getting ClamAV and Qmail-Scanner to work together. I've also written one explaining how to upgrade an existing ClamAV install on an RPM-based distro.

I have written a page which details how to use my "qfixq" script to repair a damaged queue. This page is listed on the scripts page, but I feel it also deserves a special mention here.

I have written a page which talks about how to work with qmail's log files. It will explain a few different things which can be done with the log files, such as tracing a message as it goes through the server.

I have written a page which explains how relaying works under qmail. I tried to explain how the RELAYCLIENT variable and the rcpthosts file affect qmail-send.

I have written a page which explains the so-called "silly qmail syndrome", along with a patch to fix the problem.

I have written a page which explains the issues that people seem to run into when they upgrade from qmailrocks 2.2.0 to my current combined patches.

I have written a page which explains how to set up what I call a "Mailhub", which is a machine whose only job is to handle RBL, virus, and spam scanning for mail arriving from the outside world, and forwards all "clean" messages to a dedicated mailbox server.

I have written a page which explains how to run vpopmaild under daemontools. vpopmaild is a service included with vpopmail 5.4.15 (and later) which allows clients to perform the same functions as the vpopmail command line programs, without having to SSH into the machine and run the programs directly. It also makes it possible, once I write the code to do it, for qmail-smtpd to validate an AUTH command without having to fork() and exec() another process. The page also includes a quick example of how to test the service once it's running.

I have written a page which explains how to un-install sendmail from RedHat and friends... or maybe a better description would be "how to make the RPM database believe that you have an MTA installed, even though you didn't install it through the RPM mechanism".

Related Packages

There are several other programs related to qmail which I also use on the servers I build. For the most part I am using them exactly as their authors originally intended, but there are some specific customizations I have done, particularly in the scripts which run the services involved.

• vpopmail is a package which automates and simplifies the process of hosting email for multiple domain names on one machine.

• Dovecot is an IMAP and POP3 server. I have been using it since May 2008, and have been very happy with it. I have a web page which explains how I set it up on my own server.

• qmailadmin is a web-based front end which allows the owners of individual domains to administer mailboxes, autoresponders, and mailing lists within their domain.

• vqadmin is a web-based front end which allows the owner of the server to create, modify, and remove email domains. The only thing it doesn't do is include a way to add invividual mailboxes within a domain (the idea being that the domain owner should do this using qmailadmin, rather than the machine owner having to babysit his clients' mailboxes for him.)

  I wrote a patch for vqadmin version 2.3.2 which removes a built-in limitation requiring the program to be installed with a fixed URL on the server. (It also fixes a spelling error.) This was a long time ago, I don't think this is even a current version of vqadmin anymore, and since I don't use vqadmin myself, I haven't even checked to see if these fixes were added to the mainstream code or were even looked at.

  2005-08-08: The same issue showed up again on the vqadmin mailing list... out of curiosity I just looked to see what the current version was. IT'S BEEN TWO YEARS and the "current" version is still 2.3.2!!!

  2005-09-21: I mentioned this in an email on the vpopmail mailing list- apparently they're going to try to get a new version rolled up sometime soon.

• ucspi-ssl is a set of programs which comply with djb's UCSPI standard, providing generic SSL-enabled socket services to programs which need them. Think of it as an SSL-enabled version of ucspi-tcp. My only complaint is that they bundle an unnecessary perl module with the software, and on most systems it doesn't compile correctly- which means I have to manually install the package, because the installer can't get past the fact that the perl program doesn't work unless you have the correct version of perl.

Mailing Lists

I am hosting two public mailing lists on my server which relate to qmail. One is a two-way discussion list, primarily focused on my combined patch but also open to general discussions of qmail and/or anything you see on this web site. The other is a one-way announcement list, where I announce new versions of the combined patch and any major changes to the web site.

Old HOWTO pages relating to courier-imap

I stopped using courier-authlib and courier-imap on my own server in May 2008, when the developer of courier-authlib announced that he would no longer support his own code to make courier-authlib work with vpopmail.

I now use dovecot instead.

I'm leaving these pages here in case anybody needs them, however I don't plan to update them anymore.

Running courier-imap under daemontools

Running courier-authlib under daemontools

Running courierpassd under daemontools

Building Courier-IMAP RPMs without FAM

Other Information

• The old website history (from when the site was a directory on my main web site) has been moved to a page of its own.

• I STILL receive unsolicited questions from people who seem to assume that, because I sometimes answer questions on mailing lists, I must be in the business of providing unpaid consulting services, or that I love the idea of acting as a human index of my web site, or the documentation of any number of other packages, so people don't have to be bothered with that pesky Google thing. I wrote this page as a quick and easy answer to these people.

• Several people have asked if I have a "privacy policy" for the web site. I had never really thought much about it, because it's just a static web site, and doesn't really collect any information. However, it occurred to me that this is something I look for when I visit other sites, particularly sites which are asking for my information (email address, name, phone number, and so forth.) So I wrote one to cover this site, and the same one will cover my main site once I get the file copied over to the other site.

Copyright 1995-2024 John M. Simpson KG4ZOW (email) (PGP key)
Last updated 2009-11-18 00:39:40 +0000