Given a fresh install of Ubuntu with a FQDN of example.com
$ hostname -f example.com
If user installs iRedMail (or another mail server) using demo.example.com as their first mail domain name.
His mail account is therefore firstname.lastname@example.org
What should the A and MX DNS settings look like?
Here is my attempt:
A example.com SERVER_IP A demo.example.com SERVER_IP MX demo.example.com example.com
Edit: My reasoning, is that both example.com and demo.example.com need to resolve to the server IP.
And the hostname demo.example.com should resolve to the demo.example.com for the MX record because the email@example.com needs to be processed via the main server example.com.
Is that correct?