BrT

Note: some time has passed since I wrote this article. While the general idea still holds, the dovecot configuration format has changed in recent versions, so please don’t use the file I show here blindly.

I recently switched all my locally-stored email in my work machine from Evolution 1.4 to a local IMAP server, using the Maildir folder format. The motivation for this was that I have been using Evolution (1.4) for a while, and wanted to give Thunderbird a try. But with my messages stored in Evolution’s local format, it was difficult to seriously test Thunderbird. A comment posted in this article gave me the idea I was looking for: install a local IMAP server, then you can switch email clients as much as you want, always having access to your messages. I decided to try Dovecot, the IMAP server mentioned there.

So here’s what I did.

1. Dovecot is in Gentoo’s portage tree, although the latest version is masked:

   echo "net-mail/dovecot  ~x86" >> /etc/portage/package.keywords
   emerge -v dovecot

2. The default Dovecot configuration in /etc/dovecot.conf is mostly OK. These are the lines I currently have uncommented there (this is for dovecot 1.0rc27):
   

   protocols = imap imaps
   listen = localhost
   disable_plaintext_auth = no
   shutdown_clients = yes
   ssl_disable = yes
   ssl_cert_file = /etc/ssl/dovecot/server.pem
   ssl_key_file = /etc/ssl/dovecot/server.key
   mail_location = maildir:~/.maildir
   protocol imap {
   }
   protocol pop3 {
   }
   protocol lda {
     postmaster_address = postmaster@example.com
   }
   auth default {
     mechanisms = plain
     passdb pam {
       args = "*"
     }
     userdb passwd {
     }
     user = root
   }
   dict {
   }
   plugin {
   }

   This configures it to store everything under each user’s $HOME/.maildir directory, in Maildir format, and to authenticate using the existing system accounts.

3. To convert my Evolution mail folders to Maildir format, I found the mb2md.pl script. This script can pretty much convert everything (including read/unread status, some Evolution headers, etc.). It can also do recursive conversion, but first I had to put all the Evolution folders in a structure that only contained the mailbox files. For this, I wrote this script. You run it like this:

   cd $HOME/evolution/local # Important, the script assumes relative paths
   find . -name mbox -print | xargs ./evo2mbox.sh

   It will copy all your evolution mbox files under $HOME/tmp/mboxes, named with the corresponding mailbox name. If a mailbox contains subfolders, its name will have “_f” appended, to differentiate it. Your Inbox folder will be renamed to “oldInbox” so that it does not conflict with the IMAP-provided Inbox. You can later adjust and rename things by hand as needed.

4. Finally, convert your mbox folders to Maildir:

   mb2md.pl -s $HOME/tmp/mboxes -d $HOME/.maildir -R

5. Now, start Dovecot with /etc/init.d/dovecot start, and configure your email client to connect to the IMAP server at localhost, authenticating with your Unix account and password. Hopefully, all your mail should be there.
6. I had to change my procmail configuration file so that the default rule delivers the messages to my new Maildir inbox:

   :0
   ${HOME}/.maildir/

7. I modified my local postfix configuration, so that email sent locally is also stored in the corresponding .maildir directory. In /etc/postfix/main.cf, I set:

   home_mailbox = .maildir/

I think that’s it! Drop me a comment if you find anything wrong or missing.