ChoiceMail One, by DigiPortal Software Inc., is one of the most sensitive junk mail filters I know of. It runs on your own Windows workstation, sitting between your ISP's email servers and your own mail client much like a tiny proxy server. ChoiceMail fetches your incoming email from your provider's server and processes it so that your normal email program will see your non-junk messages only.
The fundamental logic ChoiceMail follows is that incoming mail is junk unless specifically welcomed. (This principle of initial denial is more commonly applied to firewall and router configuration. Allowing only necessary traffic is usually safer than fixing leaks on a whack-a-mole basis.) In practice, messages will be accepted "from" whitelisted email addresses. An initial whitelist should be generated from your email address book. Everyone you send mail to will also be pre-emptively whitelisted. Additionally, you can have ChoiceMail apply rules you write yourself.
But what if you want to get rid of junk mail while receiving mail from persons you haven't whitelisted yet? When you get mail from an unknown address, ChoiceMail can automatically send a confirmation request to the ostensible sender, asking him to fill out a short form on a web page. If he does, you will be notified, and, based on the reason he has provided, have the option to allow or deny mail from him. On the other hand, if the sender is a "spammer", he is unlikely to respond, and ChoiceMail will automatically purge the original message after a few days.
Opponents have voiced the opinion that the confirmation requests ChoiceMail sometimes needs to send should themselves be considered junk mail. Although automatic responses are widely used, and are even required by Internet standards in some situations, it is important to remember that email addresses are easy to falsify. You should therefore make every effort to avoid challenging unrelated third parties.
ChoiceMail makes the following checks before deciding to send a challenge:
These rules are powerful. Use them as extensively as possible, falling back on the challenge-response feature only if none of them matches. Also note that you can disable challenges altogether; if you do, you will need to review the list of unknown senders manually instead.
You cannot expect to mail ChoiceMail support and receive an emailed response.
All content © 2000–2008 Thor Kottelin, unless otherwise indicated. Any trademarks or registered trademarks mentioned on this site belong to their respective owners. Content and techniques used on this site may be available for licensing; for details, please contact the webmaster.
Conventional hyperlinking to any content on this site is highly welcomed. However, the work you are viewing must not, even in part, be shown in a context inferring or claiming it to be part of, or sponsored by, any other organization or site. Such prohibited techniques include (but are not limited to) framesets, interstitial pages, kiosk mode pop-ups, and reverse proxies.