As of July 2009 dovecot replaced the old courier imap system on RedBrick. Dovecot runs on morpheus, and has a service address of .58 for imap. Dovecot is better than courier cause of it's indexing abilities. Webmail relies on this imap server to, like, work.
These docs are incomplete, but I've tried to update them with what I can remember.
We only use IMAP, on port 993. This is set in dovecot.conf
Dovecot uses the same SSL certs as apache, but keeps it's own
I had to set this manually in dovecot.conf, and manually set the permissions on the index directory.
mail_location = maildir:~/Maildir:INDEX=/var/mail/indexes/%u
$ ls -ld /var/mail/indexes drwxrwsrwt 58 root mail 4.0K 2009-07-28 14:11 /var/mail/indexes
Originally when it was in testing on deathray dovecot talked to ldap for usernames/passwords, but this seemed to break on the morpheus migration, so it is currently (at least, as far as I can remember) set to use pam instead.