Whilst the world seems to be moving email to “The Cloud”, rightly or wrongly I remain reluctant to give up the control of our own mailserver. For over ten years now we have been using a combination of the following open source applications:

• Postfix MTA with Amavis + Spamassassin
• Dovecot IMAP server
• OpenLDAP

Whilst these are super-stable and bulletproof solutions, the main issue with such a solution is the administration - setting up users, changing passwords, vacation notifications, sieve etc. It is also a lonely business administering a custom mailserver, where set-up is never going to be completely standard.

A couple of years ago I migrated to a new mailserver, on which I installed iRedMail. iRedMail is a pre-packaged mailserver solution, based on all the software that I was using already (Postfix, Dovecot, OpenLDAP), but with the benefit of a slick admin panel that pulls it all together and provides ongoing support. It also incorporates Roundcube for webmail, undoubtedly prettier than Squirrelmail, which we were using before. iRedMail even includes a pre-configure Fail2ban, essential to protect your internet-facing server from attack.

There are two web administration panels to choose from - the free and open source panel and the Pro panel. Both interfaces are attractive and functional, but predictably the Pro panel has more functionality at a price. Some would call this Crippleware, but bear in mind that the server itself has full functionality - this is merely the configuration of that server. If you are happy to configure LDAP yourself, then you don’t strictly need to use the Pro panel. See “Features and Comparison” half way down this page. Whilst the Pro panel does come with the source code, the developer explicitly restricts your right to distribute.

Installation is very fast - but must be on a fresh server - I tried to upgrade from an existing Postfix install and it ended badly. Updates are delivered as a web page of instructions, which I have come to prefer to running an upgrade script, as you can intelligently decide whether you are happy with each change proposed. The downside is that you could easily miss a step and leave your server only partially “upgraded”.

Whilst the forums are quiet, the developer is very responsive to posts and has dealt efficiently which each issue that I encountered. Roundcube has proven to be a very attractive webmail interface and includes Sieve administration for server-based filtering and vacation notices.

Overall we are very happy iRedMail users - if there is an easier way of running an Open Source mailserver, I have not discovered it.

1. If your mailserver is running IMAP, then what are you doing here? Just connect your Linux mail client to your IMAP server and you’re good to go!
2. If you are running a common mail client on Windows, then consider installing Mozilla Thunderbird on Windows and importing your emails into that… a. See Transfer Emails from Microsoft Outlook
3. If you are running Mozilla Thunderbird on Windows, then you can simply copy the files onto Linux and use Mozilla Thunderbird on Linux - job done.
4. If your Windows email client stores in mbox format (unlikely) then again you should be able to simply copy the mail store to Linux.
5. Check whether you have any export options and see if you can export into an easier format, e.g. Thunderbird/MBOX.
6. If your Windows email client does not support IMAP, then you will need to upgrade it to a more recent version that does before proceeding.
7. If your Windows email client does support IMAP, then let’s continue…

Install Courier-IMAP on server

See Install Courier-IMAP Server

Create LTSP User

In KUserManager create the user, and add to the following groups:

• kiosk-standard
• Staff
• Users
• Fuse (only if you want them to be able to access USB devices)
• Saned (only if you want them to be able to use scanning)

Take a note of UID and GID before exiting KUserManager

Create IMAP Account

You need to have installed an IMAP server first - see page Install Courier-IMAP Server

$ sudo userdb USERNAME set uid=9999 gid=9999 shell=/bin/bash home=/opt/imap-mail/USERNAME

*Replace USERNAME and 9999 for actual username, uid and gid

$ sudo userdbpw -md5 | sudo userdb USERNAME set systempw
$ sudo mkdir -p /opt/imap-mail/USERNAME
$ sudo maildirmake /opt/imap-mail/USERNAME/Maildir
$ sudo chown -R 9999:9999 /opt/imap-mail/USERNAME
$ sudo makeuserdb
$ sudo /etc/init.d/courier-authdaemon stop
$ sudo /etc/init.d/courier-imap stop
$ sudo /etc/init.d/courier-authdaemon start
$ sudo /etc/init.d/courier-imap start

*Replace USERNAME and 9999 for actual username, uid and gid

Key steps

The rest of the process is simple enough, that hopefully I do not need to go through it in detail. Briefly:

• Install Courier-IMAP Server
• Create IMAP account in Windows email client
• Log onto LTSP
• Kontact → Mail → Create IMAP account
• Transfer each mail folder into IMAP Inbox then transfer each IMAP folder into Kmail folder
• Repeat last step for each folder

Change each client to work off-line between transfers - you don’t really want both clients connected to the same IMAP mailbox at the same time

Courier-IMAP is quick and easy to install, but is probably not your best option for running a first class IMAP server. In particularly I have been strongly recommended Cyrus IMAP server. The big advantage to Courier-IMAP is that it can be very easily installed on your LTSP server as a temporary migration tool for email, i.e. to transfer users from Windows to Linux.

Install IMAP

$ sudo apt-get install courier-imap

This will prompt whether to create files for use by the web interfaces; it is safe to select “No” here.

Now you need to choose a directory where your mail will live:

$ sudo mkdir -p /opt/imap-mail

Now we need to define our users in the courier-imap user database. There are several ways to do this, including mass conversion of all your users in /etc/passwd using the pw2userdb tool as mentioned in the courier FAQ. Here is what we do to create a single user:

$ sudo touch /etc/courier/userdb
$ sudo chmod 600 /etc/courier/userdb
$ sudo userdb ~userid~ set uid=<1000> gid=<1000> shell=/bin/bash home=/opt/imap-mail/~userid~

*Edit the final line as appropriate.

Now you need to set the users password and create the directory that will store all our e-mail:

$ sudo userdbpw -md5 | sudo userdb <peanut> set systempw
$ sudo mkdir -p /opt/imap-mail/<userid>
$ sudo maildirmake /opt/imap-mail/<userid>/Maildir
$ sudo chown -R <1000>:<1000> /opt/imap-mail/<userid>

In the /etc/courier/authdaemonrc file, make sure you set the following value:

authmodulelist="authuserdb"

Note that you may need to replace the existing authmodulelist value. Now prepare the user DB and restart the entire system:

$ sudo makeuserdb
$ sudo /etc/init.d/courier-authdaemon stop
$ sudo /etc/init.d/courier-imap stop
$ sudo /etc/init.d/courier-authdaemon start
$ sudo /etc/init.d/courier-imap start 

The IMAP system is now ready.

References

• http://www.howtoforge.com/converting_outlook_pst_to_maildir