Thanks for bringing this up on the forums, Scott!
Regarding Scott's comments . . . I've been researching the bitmap checking capabilities of both the RBLs included in my antispam document as well as those not included, and have found nothing, on any of the RBL database websites, to indicate whether or not they support bitmap checking.
In the e-mail traffic that has taken place between Scott and myself, he brought up the fact that my current document (as of 31 Dec, 2015), included at least one RBL which had bitmap checking enabled and wanted to know what my experience was with how a rough bitmap might be handled.
My response was, and still is: I have no idea. I've seen nothing and have nothing to report on whether or not this is actually checked by any RBL database providers.
So, group(s): anyone else have anything to contribute with regard to RBL bitmap checking?
Phone: (224) 444-0169
E-Mail and DNS Security Specialist
Network Security Specialist
Customer Service Portal: https://portal.chicagonettech.com
Security Blog: http://networkbastion.blogspot.com/
Web and E-Mail Hosting, E-Mail Security and Consulting