I set up a mail server following the perfect-server-ubuntu-10.04-lucid-lynx-ispconfig-3 how to. After a certain amount of tweaking I've got it working very well except for one thing. Spam email is caught (very accurately) and marked by insertion of "***SPAM***" in the subject line. The spam is not automatically moved to the Junk folder however; it just stays in the Inbox. Under Mail Filters I have checked the box to automatically move spam to the junk folder and even tried creating a rule to look for ***SPAM*** in the subject line and move it to the Junk folder. Neither works. In searching for others having this problem I have found others with the problem but no definitive answer. I did notice one place where a moderator said that mail filtering is handled by maildrop. I have virtual_transport = virtual in postfix main.cf. Could that be part of the problem? If I set virtual_transport = maildrop, nothing works - incoming and outgong mail cannot be authenticated and is rejected. When set to vitrual everything works great, and fast - except for moving spam to the Junk folder. Frustrating! Has anyone come up with a solution to this yet?