A number of our ISP partners have been using the Sender Score to inform their rate limiting algorithm, permitting IPs with a higher score to send at a higher rate, while those with lower scores are restricted to lower rates of delivery attempts.
Recently Peter Blair, IT Security Specialist at Tucows, released some code which should allow anyone to use this same technique.
If you don’t already have a local copy of the Sender Score zone, set $ZONENAME to score.senderscore.net — though if you’re going to be making a lot of queries (such as at an ISP or large institution), please talk to us about getting a local copy before you put this into production. Be sure to mention this article.
Let us know how it works for you.