Setting up a mail server, what about records?

Question

Domain Name System

Here are the records that, as I understand it, are necessary for the normal operation of the mail.

mail IN A 11.22.33.44
pop IN A 11.22.33.44

Everything is cool, but now you can get to my site through these subdomains.
mail.example.com
pop.example.com
And this is a duplicate. How is it done correctly?

Answer 1

for mail - mx records
https://serverpilot.io/community/articles/how-to-c...
and so that the site does not open by mail.site.com and pop.site.com from configure virtual
hosts
https://www .digitalocean.com/community/tutorials/h...