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The Bottom Line
Spam Interceptor is an elegant, easy to use and flexible, but most of all effective spam filtering solution. Its combination of multiple strategies works great — unfortunately for POP accounts only. Spam Interceptor is no longer available.
Pros
- Spam Interceptor combines challenge/response and scoring filters
- Elegant, simple and effective, Spam Interceptor is a joy to use
- Spam Interceptor can filter based on a sender's average spam score
Cons
- Spam Interceptor supports POP accounts only
- Spammers using whitelisted addresses get through
Description
- Spam Interceptor intercepts spam before it reaches your email client's Inbox.
- Working as a filtering gateway, Spam Interceptor fetches mail from your POP account periodically.
- While you use Spam Interceptor through a nice web interface, mail can be downloaded using POP.
- Spam Interceptor uses heuristic filters to determine each message's spam score.
- Low-score mail always gets through and mail with a high score is always blocked.
- Senders of mail with a score in between are sent a challenging message to which they must respond.
- Spam Interceptor can also filter based on the average score mail from a certain sender gets.
- All thresholds can be configured, challenging can be turned off completely.
- Trashed mail can be recovered easily through Spam Interceptor's web interface.
Guide Review - Spam Interceptor - Spam Filtering Service
Challenge/response spam filtering — only mail from known senders is allowed through, and new senders must respond to a challenge to "authenticate" — works effectively, but it has a number of flaws, too.
Spam Interceptor makes smart use of challenge/response filtering while escaping most of its drawbacks by placing a scoring filter in front of it. Mail that's certainly not spam is always allowed through while senders of mail with a large score aren't challenged either. Their mail is simply trashed (but easily recoverable).
Spam Interceptor can even filter based on the average score of mail from a sender, so you get away without using black and white lists a lot and still have most of the spam filtered out with little to no false positives.
