2018-11-13 18:24 GMT+01:00 Viktor Dukhovni <postfix-us...@dukhovni.org>:
> > On Nov 13, 2018, at 11:48 AM, Wietse Venema <wie...@porcupine.org> > wrote: > > > >> It's colonel.com.pl. Please check. I don't see anywhere MX's IP as A > record > >> in dns zone. > > > > You have both A and MX records for colonel.com.pl. Some SMTP systems > > may try to send email using the A record, if those SMTP systems are > > borked and if their DNS resolver is borked. > > In other words, nothing to worry about. There's no need to worry about > such broken systems in practice. Real MTAs don't get this wrong (though > perhaps what I'm saying is that if there are some MTAs that get this wrong, > they are garbage that deserves to be ignored). > > -- > Viktor. > > [1] https://en.wikipedia.org/wiki/Infinite_monkey_theorem Ok, thank you guys for answers and advices. Appreciate! -- *Pozdrawiam / Best Regards* *Piotr Bracha*