MailBox Sentry" is "The Swiss army knife" among anti-spam systems. Whether you prefer all-round defense or you are in correspondence with many addressees, if you receive a few spam messages or a lot of spam - everyone can find to himself the tool on taste... "The big brother keeps up with you": at sending mail "MailBox Sentry" will find out the new addressee and will suggest to put him into white list or to supply the letter with the password. The program stores some information about your addressees and will pass the replays and the delivery error messages without superfluous questions. "MailBox Sentry" analyses what sites you visited and passes registration notification messages.
If you receive a few spam messages or prefer to look through all new mail manually, the program will offer you a mode (which is called "Ask me") viewing of incoming mail, preliminary having processed and having passed all "legitimate" correspondence. So you should apply much less efforts for "washing" mail.
If you receive a lot of spam at your service powerful system "challenge/response" (the brief idea of such systems is that the all new correspondents should confirm sending the letter to you. "Legitimate" correspondents can do it but not spammers). "MailBox Sentry" has been developed in conformance of all requirements to such systems. The program doesn't send to one address more than one challenge, dead loops is impossible, it sends challenges to the authors of the messages from newsletters lists, etc.