A modern, fast web-mail client with user-friendly encryption and privacy features

How to setup OpenDKIM to avoid the frustration of getting falsely flagged as a spammer

DigitalOcean guide to setup an SPF Record to prevent your mails from being blacklisted

How to set hostname and FQDN on your Linux box

Probably out-of-date but can still hold useful information

Discussed @ Archlinux bbs

Discussed at Server Fault