That is a very good suggestion and it is my highest priority as well, in terms of "thinking about improvements to email".
I do understand the attraction of highly specialized, modular and pluggable tools - so I know why OpenSMTPd does not have a built-in nameserver, spam filter or DKIM service. The architects are thinking about correctness and scalability and modularity, etc.
But Oh My God it would be so much simpler - and comprehensible - if there was just one package with just one config file.
If the only purpose of a particular nameserver is authentication tasks for a mailserver, we should consider moving the nameserver into the mailserver. The same goes double for dkimproxy.
You're describing new solutions like Stalwart and Maddy. Which try to automate away a significant portion of these issues and maintainability concerns.
I do understand the attraction of highly specialized, modular and pluggable tools - so I know why OpenSMTPd does not have a built-in nameserver, spam filter or DKIM service. The architects are thinking about correctness and scalability and modularity, etc.
But Oh My God it would be so much simpler - and comprehensible - if there was just one package with just one config file.
If the only purpose of a particular nameserver is authentication tasks for a mailserver, we should consider moving the nameserver into the mailserver. The same goes double for dkimproxy.