SPF flattening replaces include: mechanisms with the actual ip4:/ip6: ranges they resolve to, eliminating DNS lookups to stay under the 10-lookup limit. It works, but it’s fragile: when a provider changes its IPs, a static flattened record breaks. Use an auto-updating service and monitor it.
Because ip4:/ip6: mechanisms cost zero DNS lookups, converting includes to IPs removes lookups and resolves PermError. It’s a direct fix for “too many DNS lookups.”
Providers rotate IPs. A hand-flattened record silently fails when they do, bouncing legitimate mail. If you flatten, use a managed service that keeps the record current, and prefer removing unused includes first.
Check your SPF record now
Open the free SPF checker →Only with automation that updates the record when providers change IPs. A static flattened record is a known cause of sudden deliverability failures.
