Courier-IMAP

Prerequisites
Courier installation requires the gdbm development tools:

Courier-Authlib
The Courier authentication library provides authentication services for the Courier programs which we'll be using on our server to provide IMAP and POP3 on the mail server. While it does support system passwords, LDAP, and MySQL, we'll be using authvchkpw to integrate it with vpopmail.

Download the latest tarball:

Create a "go" file to contain the config options:

Execute the go script, then make and install the binaries:

Edit the config file /usr/local/etc/authlib/authdaemonrc for the daemon so that it only uses the authvchkpw module:

Might need to increase the number of daemons if you experience authentication failures:

Like the other services, we'll use daemontools to make sure that the authentication daemon is running:

Edit the /var/service/courier-authlib/run file to reflect where the programs were installed:

Make it executable and set up the log script:

If it doesn't start, you might have a problem with libltdl.so.3 not being found (check the log). It seems to happen with the latest versions of courier-authlib. You can fix that with:

Courier-IMAP
The binaries for Courier-IMAP cannot be compiled as the root user so we'll create an unprivileged user for that purpose:

At time of writing, the latest version of Courier-IMAP was 4.3.1 but you might want to check for a newer version. Otherwise, download the source file:

Switch to the couriercompile user:

Create a go script to contain the configuration options:

Then configure and build the binaries:

Then switch back to root and install the programs:

Edit /usr/local/etc/imapd.cnf, then run mkimapdcert to generate an SSL certificate for use by Courier:

Edit the /usr/local/etc/imapd config file for the imap daemon. The MAXDAEMONS value might vary depending on how many concurrent IMAP users you expect to have. MAXPERIP might need to be increased if you have individual users connecting to more than one IMAP account simultaneously.

NOTE: If you increase the MAXDAEMONS past 40, you'll need to adjust /service/courier-imap/run so that tcpserver allows more than the 40 connections specified in the run script:

The imapd-ssl config file, /usr/local/etc/imapd-ssl needs modifications too:

Courier IMAP 4.2.0 changed some SSL stuff that Thunderbird doesn't like. You'll need to adjust TLS_PROTOCOL:

Daemontools Service Setup
Big surprise, we're going to use daemontools to manage the various Courier services.

First, a regular, unencrypted IMAP service:

Edit the /var/service/courier-imap/run file to reflect where we have Courier-IMAP installed:

Install the log scripts and start the service:

Then, an SSL-encrypted IMAP service. This is the one that users should connect to from outside your LAN:

Edit the run file to reflect where we have Courier-IMAP installed:

Install the log scripts and start the service:

If you are going to have POP3 access, this one is an unencrypted one for LAN users:

Edit the run file to reflect where we have Courier-IMAP installed:

Install the log scripts and start the service:

Set up an SSL-encrypted POP3 service if you want to give users POP3 access from outside your LAN:

Edit the run file to reflect where we have Courier-IMAP installed:

Install the log scripts and start the service: