What services are used and what tasks are performed when running Postfix or Exim?

Question

Exim

I am new to Linux. The other day they asked a question.
What services are used and what tasks are performed when running Postfix or Exim?

Answer 1

man postfix, man exim. I also recommend reading the book "Postfix administration", there is a translation into Russian. It describes in detail which process is responsible for what. rtfm in general)

Answer 2

any mailer is the reception of the transmission of mail. each has filters, that is, elementary spam protection can be configured. You can connect an antivirus to each, both paid and free, there is a choice. You can configure smtp authorization (login-password verification when sending),
etc.