I am looking for a powerful anti-spam solution to propose to my customers. This should be something that they install on their computers and integrates well with their email clients. It would be nice if it's opensource but a paid solution will do as well. The platform should be Windows. Thanks all in advance!!
MailWasher a (client independent) spam filter which retrieves information about all the emails on the server. With that information (some of which is also processed by MailWasher) you can decide what to do with each individual email - download, delete, or bounce back.
if the your clients using Outlook 03 or OE6 then defNULLspam is certainly a force to be reckoned with.
two different methods but each highly efficient in their own way and free.