Read : http://www.sorbs.net/faq/rfc_helo_enforcement.shtml
I contains also the links to the RFC’s Greetz, Louis Van: zalezny.niezale...@gmail.com [mailto:owner-postfix-us...@postfix.org] Namens Zalezny Niezalezny Verzonden: dinsdag 10 november 2015 13:30 Aan: Postfix users Onderwerp: receiving message - checking mx record by postfix Dear Colleagues, I would like to understand how Postfix receiving message. I expect that Postfix has been written base on the RFC rules so maybe somebody will be able to explain me how its working inside - how this system receiving message and what is going on in the background. Our consultant hardly trying to tell us that server during receiving phase checking MX record of the domain from which coming the E-mail. Does it really working this way ? I always thought that Postfix checking first DNS A record (reverse dns), then SPF etc.etc. I always thought that MX record is provide clear information about the servers to which client needs to send a message. But right now I`m completly out of space... Does system check mx record when its receiving message or not ? Do You know where may I find RFC which fully describing this SMTP process ? With kind regards Zalezny
