I like to use extended email addresses, or aliases I can make up on the fly. I mean addresses like email@example.com When someone wants my email address, I make up one which represents the company that asked for it. That way if I get spammed, I can filter that out, and I know who did it. For example, if I subscribe to the ABC newsletter, I can give them my email address as user-ABC@mydomain.com and the newsletters will be delivered to firstname.lastname@example.org I tried to modify the postfix and courier config files, but this did not work. But I found its incredibly easy to add an Email --> Global Filters --> Content Filter to do the job through ISPC3. Example: Set Pattern to: /^.*USER[+-].*@YOURDOMAIN.COM.*$/ and Action to REDIRECT and Data to USER@YOURDOMAIN.COM This will accept either + or - as the delimiter. I hope this is useful for someone.