UW IMAP
Although UW IMAP has not been actively developed in many years, it still works well as a basic IMAPS server. (For other IMAP servers, see Mail server#POP3/IMAP servers.)
Installation
Install imap. It does not use a configuration file.
Setup
Although it was originally designed to be used with inetd, on modern Arch systems a better solution is to use a systemd socket file:
/etc/systemd/system/imaps.socket
[Unit] Description=IMAP Server Activation Socket Documentation=https://www.washington.edu/imap/ [Socket] ListenStream=0.0.0.0:993 Accept=true [Install] WantedBy=sockets.target
Also, a corresponding .service file needs to be created:
/etc/systemd/system/imaps@.service
[Unit] Description=IMAP Server [Service] ExecStart=-/usr/bin/imapd StandardInput=socket
UW-IMAPD uses PAM, so a PAM authorization file will also need to be created. This example will provide authentication using standard system passwords:
/etc/pam.d/imap
auth required pam_unix.so account required pam_unix.so session required pam_unix.so
Enable and start imaps.socket
and test.
SSL
A generic SSL certificate and key will be created at /etc/ssl/certs/imapd.pem
if it doesn't yet exist. This can (and should) be replaced with a signed certificate for the specific server.