Spam blocking with sender_access in postfix itself.
This is kinda a pet peeve with me. I hate spam. I have my own email servers hosted locally at my shop because I dislike other entities contacting me without my explicit permission. If I suddenly get spam from some entity I want to ensure I have full control to block everything from their domain. That is what I thought I had done and it seemed to work for some time, however, I started getting spam from several entities that I thought I had blocked, and after checking found that I had blocked them. I went looking for answers and found the answers were in the details. I read posts pretty fast and sometimes just exclude them from the solution due to how little detail or how much detail they…