CEAS paper: "SMTP Path Analysis" using SPF and reputations

On SPAM-L, Steven Champeon mentioned the following paper:

 http://www.ceas.cc/papers-2005/176.pdf


Here is the abstract.  I haven't read the entire paper, but what I
have read looks very promising.



                      Abstract
    
    Most proponents of domain authentication
    suggest combining domain authentication with
    reputation services. This paper presents a new
    learning algorithm for learning the reputation
    of email domains and IP addresses based on
    analyzing the paths used to transmit known
    spam and known good mail. The result is an
    effective algorithm providing the reputation
    information needed to combine with domain
    authentication to make filtering decisions.
    This algorithm achieves many of the benefits
    offered by domain-authentication systems,
    black-list services, and white-list services
    provide without any infrastructure costs or
    rollout requirements.


-wayne