On 2018-11-14 08:21, Poliman - Serwis wrote:
2018-11-13 19:58 GMT+01:00 Wietse Venema <wie...@porcupine.org>:
You man still want to turn off the SMTP listener on colonel.com.pl,
because it will never receive legitimate email.
Wietse
Thank you for answer. I suppose I don't understand properly. How could
I do this if this
domain has MX on Google?
If your e-mail is handled by Google, then you should not have an SMTP
server running (listening) on colonel.com.pl.
So you should go (ssh) to colonel.com.pl and
disable/deinstall/firewall/etc. postfix so that it does not accept
incoming e-mails (e.g. ports 25, 465, 587).
If anyone wants to send you an e-mail, the MTA (sending server) will
lookup colonel.com.pl and find the relevant MX record pointing to
Google. The MTA will then send the e-mail to the Google server.
In severely broken situations an MTA might decide to try to send it
directly to colonel.com.pl and -- surprise -- find a welcoming
(listening) SMTP server. You don't want that, so, again, you should
disable/remove/uninstall the SMTP server on colonel.com.pl
Hopefully this is clear now.
