Courier-IMAP is a popular IMAP server implementation that I have been playing a lot with at work lately. We make heavy use of MySQL for authentication, accounting, and lookups where possible, making Courier-IMAP's MySQL authentication module appealing to us. While basic authentication using MySQL works out of the box, there are two additional things that we try and support. One is knowing when a given user has last checked their mail, and another is supporting POP/IMAP before SMTP so roaming users can send mail through our SMTP servers.

Both of these features can be implemented by executing SQL queries after a successful login, which is not supported out of the box. Therefore I wrote a patch for Courier-IMAP that provides IMAP before SMTP and "mail last read" support by executing two SQL queries after the user logs in. Both of these SQL queries can be changed/disabled in the authmysqlrc file.

This patch was created against Courier-IMAP version 3.0.4, so I recommend that you use this version if at all possible. You will need to download it below.

courier-imap-sql-updates.patch

Untar the Courier-IMAP source and copy the patch file into the source directory. You can apply the patch to your source tree by executing the following command.

patch -p1 < courier-imap-sql-updates.patch

Now you can configure, build, and install Courier-IMAP like you normally would.

After finished installing, you will need to edit your MySQL authentication config file which is usually located at /usr/lib/courier-imap/etc/authmysqlrc. The two new configuration options that have been added are MYSQL_QUERY_LASTREAD and MYSQL_QUERY_POPB4SMTP. You will need to define the SQL queries that should be executed after each login for both of these options. The %s variable for the MYSQL_QUERY_LASTREAD option will be substituted with the user's full login name, while the user's client IP address will be substituted with the MYSQL_QUERY_POPB4SMTP option.

Below is an example of these two configuration options in action.

MYSQL_QUERY_LASTREAD    REPLACE INTO mail_last_read (address, tstamp) VALUES ('%s', NULL) MYSQL_QUERY_POPB4SMTP   REPLACE INTO mail_pop_before_smtp (ip, expires, email_local, email_domain) VALUES (INET_ATON('%s'), NOW() + 1800, '%s', '%s')

Someone has been kind of enough to take on the task of rewriting this patch for courier-authlib 0.56. Although this patch is untested by me, I hope someone finds it useful.

Download the updated patch

A few people have asked me about Courier-IMAP version 4 support for this patch. Unfortunately, I no longer work for the organization that I originally wrote the patch for. I am also told that the authentication code in version 4 has been completely reworked.

Luckily, a user was nice enough to point me towards a page containing a comprehensive list of POP/IMAP before SMTP solutions for postfix. It looks like the pop-before-SMTP.pl script has a versatile log-based solution to the POP/IMAP before SMTP problem.

11/26/2004: Update patch from 3.0.4 to 3.0.8.
09/03/2004: Update patch from 3.0.3 to 3.0.4.
05/10/2004: Update patch from 2.2.1 to 3.0.3.