Maybe a “Best Practice” page or “checklist for a nice migration” could be the right way to summarize a way to migrate or create a good mail server.
Unfortunately my english is not sleek and catchy enough for being concise, clear and effective.
This should include (IMVHO)
- Data collect for get all the informations needed
- Steps to be done to install, add modules, configure data, users and aliases
- Steps for migrate mailboxes and preferences (import from files, POP3/IMAP collect, IMAP transfer via client)
- Steps for protect server (antivirus check, fail2ban setup, password set)
- Steps for start data transfer to the real world (DNS, MX Record, port forwarding)
- Steps for improve reputation for not being marked as spam (TLS Certificate, SPF, DKIM, DMARC)
- Steps for improve SPAM detection
This should be a “scenario” detailed enough to help conscious and skilled enough sysadmins (even junior ones) to have the full toolbox for adapt it to their environment.
Also, concise enough to be a four A4 printed sheets (plus one for data collect) to kickstart any installation.
(the document should be unrelated to groupware or webmail, but also suggest to look for both of them before take a direction or another)