Good day, I would like to protect/restrict one of our email (distribution list) addresses from receiving emails from external domain senders. I have been searching the forum and came across this post : https://www.howtoforge.com/communit...sending-mails-outside-the-organization.81514/ I don't quite follow the instructions suggested on the post. I have also had a look at the postfix RESTRICTION_CLASS_README page. Tried out the solutions proposed on the postfix site, but I was not successful with the attempt. Any suggestions on how to go about achieving this on ISPConfig 3? Thank you in advance for your assistance.