|I have white-listed an e-mail address, but his mail from this e-mail address still gets flagged as spam! Why?|
The spam filter white-lists are not only based on e-mail addresses, but also on the path the mail followed across the Internet. This makes it almost impossible for a spammer to slip through the defences by forging e-mail from a white-listed address. However, this has the side-effect that for people sending mail from multiple locations, you may need to white-list them more than once.