Introduction

Courier IMAP is, in my very humble opinion, the best IMAP server around. I tried a few before I settled on it and it was good enough that I decided to go with the whole Courier suite. The IMAP server can be used with mail servers other than Courier SMTP but I like to keep the whole system from one house. This article is part of a series of articles on setting up the Courier mail system that can be found on this site.

Install Courier IMAP

Installing Courier IMAP couldn't be simpler. Select the packages: courier-imap and courier-imap-ssl in aptitude or other package manager. During the install of courier-imap-ssl the package will create a self signed certificate so that secure, but unverified, connections can be made to the IMAP server.

Configuring Courier IMAP

As with the SMTP server I wanted to make sure that my system was secure to the best of my ability. For this reason I have opted to have clients connect to the server over an SSL secured link that runs on port 993 which is provided by the courier-imap-ssl package. The clients will, of course, also have to authenticate themselves with the server before they have access to the mail boxes.

If all you want is secure, standard install that's all there is to it. Open port 993 (and optionally 143) and away you go. Courier only appears to accept plain, CRAM-MD5 and CRAM-SHA1 logins for IMAP and authpam can't be used with either of the CRAM flavours so you are stuck with plain. That isn't really an issue if you have an SSL connection though as the whole link is encrypted.