DNSBL

This document describes an email authentication method compliant with RFC 8601. The method consists of looking up the sender's IP address in a DNS whitelist. This document provides information in case the method is seen in the field, suggests a useful practice, and registers the relevant keywords.

This document does not consider blacklists.

The rise of spam and other anti-social behavior on the Internet has led to the creation of shared DNS-based lists (DNSBLs) of IP addresses or domain names intended to help guide email filtering. This memo summarizes guidelines of accepted best practice for the management of public DNSBLs by their operators as well as for the proper use of such lists by mail server administrators (DNSBL users), and it provides useful background for both parties. It is not intended to advise on the utility or efficacy of particular DNSBLs or the DNSBL concept in general, nor to assist end users with questions about spam. This document is not an Internet Standards Track specification; it is published for informational purposes.

The rise of spam and other anti-social behavior on the Internet has led to the creation of shared blacklists and whitelists of IP addresses or domains. The DNS has become the de-facto standard method of distributing these blacklists and whitelists. This memo documents the structure and usage of DNS-based blacklists and whitelists, and the protocol used to query them. This document is not an Internet Standards Track specification; it is published for informational purposes.