usage policy is relatively clear that it’s free, except maybe for big for-profit oranizations
listing policy is documented
return codes are documented
+ seems very trustworthy
http://www.sorbs.net/
good reputation
- seems sensible
- different kinds of lists
+ lists domains/URIs
+ lists IPs
+ usage policy is clear that it’s free
+ listing policy is documented
+ return codes are documented
+ seems trustworthy
http://www.spamhaus.org/
good reputation
very well done
- different kinds of lists!
+ seems very professional
+ lists domains/URIs
+ lists IPs
+ usage policy is clear
+ https://www.spamhaus.org/organization/dnsblusage/
+ listing policies are clearly documented
+ return codes are clearly documented
http://www.surbl.org/
http://zapbl.net/
https://rbl.foobar.hu/