GripList

From ASSPSMTP

ASSP collects statistics from participating ASSP users to help identify mail hosts that tend to send more spam or more not-spam mail. These statistics are compiled together to create a "GripList"(Grey IP List)

The GripList associates IP addresses of mail sending hosts with their recent statistical probability of sending spam or not spam. It's not a whitelist, or a blacklist, but somewhere in-between -- a grey list. Of course it is rare to find a host that sends equal amounts of spam and not-spam, so very few entries are 50/50 or completely grey.

This type of information is of practically no value to traditional IP-based spam-blocking systems. However, it is ideal for a Bayesian discriminator: this probability is factored in with other probabilities associated with the mail and helps affect the outcome in the desired way -- better spam AND not-spam detection.

ASSP takes some care in how the user-supplied statistics are handled in order to reduce the probability that a spammer or misconfigured host will unduly influence the statistics. Because strong security is impractical in this situation I prefer to leave the exact method obscure. Nevertheless, as the ASSP community grows the effectiveness of the GripList will also increase.