It turns out that today i started trying MAMP PRO for Postfix SMTP. But i had and have a nasty problem. There's no way MAMP PRO 4.2.1 is allowed to overwrite the hosts file, and it needs to, so MAMP PRO doesn't work. I found no clear answer in the internet and i tried already couple of solutions with no success, like recreating the file, erasing or commenting the 127.0.0.1 localhost line, among others. Any ideas around?