This document describes what types of blocklists are used by SenderBase.
What types of blocklists are used by SenderBase?
The SenderBase Reputation Service (SBRS) provides an accurate and flexible way for you to reject or throttle systems suspected to be transmitting spam based on the connecting IP address of the remote host. The SBRS returns a score based on the probability that a message from a given source is spam, ranging from -10 (certain to be spam) through 0 to +10 (certain not to be spam).
An important component of the SBRS score for any IP address is its presence on other DNS-based blocklists. SBRS uses over 2 dozen different DNS-based blocklists, weighted in varying ways, to contribute to the SBRS score. Some of the blocklists, such as SORBS, actually have multiple lists associated with them depending on why a system was listed in their database. There are other components of the SBRS score, such as level of complaints about the IP address and mail volume, however the exact components and blocklist's weight used in the SBRS scoring algorithm change over time and are proprietary.
Some of the main DNS-based blocklists "families" used by SenderBase include: