But email does work that way. On my mailserver, I make the rules. I decide how my spamfilters, greylisting and blacklisting is tuned. I decide who is allowed t

But email does work that way. On my mailserver, I make the rules. I decide how my spamfilters, greylisting and blacklisting is tuned. I decide who is allowed to have an account. And therefore, I decide what is allowed to be sent and received.