Hello I have an Ubuntu 16.04 server with ISPConfig 3.1 and many websites installed. I also set up Postfix with an SMTP relay service for reliable email delivery (TurboSMTP). I want to use the Postfix Blacklist feature in order to block emails sent from the following address: [email protected]. That address is sending spam and I don't know how (I don't have any website created with that domain name). First, I trying to use the blacklist feature with an email address from my own server. I added the blacklist record, but somehow it is not working and I still can send emails from that address. Any ideas about how to block those emails?