Environment: Postfix 3.3, Centos 8, Digital Ocean Droplet
I'm reading the Postfix basic configuration readme and I came across a definition I don't fully understand.
Under the heading, What domains to receive mail for it goes over the
mydestination parameter and includes this sentence,
IMPORTANT: If your machine is a mail server for its entire domain, you must list
I believe that warning is referring to this line in
main.cf. Below is the default value.
mydestination = $myhostname, localhost.$mydomain, localhost
Unfortunately I'm not exactly sure what that warning means.
On my server I have an NGINX reverse proxy, a Node.js Express server and the Postfix/Dovecot setup.
Question: Because I only have a single mail server does that mean it covers my whole domain and I need to use
$mydomain? Or are they saying that because I also use the server as a web server the mail server doesn't represent the entire use of the domain and I shouldn't include
$mydomain? Does it mean something else? I can't tell what they mean.
Not necessaryly, you can delegate a mail destinated to a subdomain to another server. For for instance: example.com use a diferente server than submain.example.com that's mean you are using two postfix server.
If you set:
mydestination = $myhostname, subdomain.$mydomain
You are saying "OK Accept mail destinate to "hostname" and subdomain.example.com
Edited: You can use a diferente public IPs for each postfix server or subdomain.