Hi there, nn a website (https://www.linuxbabe.com/mail-server/block-email-spam-postfix) I found some settings to improve SPAM rejection. One of the suggestions there were to add the value reject_unknown_reverse_client_hostname to the smtpd_sender_restrictions. But this setting is overwritten as soon as I make changes using the ISPConfig UI. Now my questions: Does this setting bring any improvements? (i.e. do I want to add that?) Is there a way to protect this setting from being overwritten by ISPConfig? Or would it be an idea to include that in future versions? Kind regards Thomas
I would say postfix set up by ISPConfig already rejects emails from sender with no PTR record. Pretty much every e-mail server nowadays does that. Are you running RSpamd on that host? If yes, you would get better results tuning rspamd settings and maybe using fail2ban (my signature has link to fail2ban tutorial).
