October 2026
SPF Flattening Explained: Benefits, Risks, And When To Use an SPF Flattener
SPF flattening is the process of converting an SPF record that relies on external references—especially the include mechanism—into a flattened SPF record containing direct IP address values or IP ranges. Instead of asking receiving email servers to follow multiple include paths during SPF validation, the domain publishes a static IP list that represents the authorized…