SPF Record Explained
Understand what SPF authorizes and how to investigate missing or duplicate records.
Login2Cloud product team · Published 2026-09-27
What SPF checks
SPF lets a domain describe which senders may use it in the SMTP envelope identity. It does not, by itself, authenticate the visible From header a person sees. Receivers evaluate the policy against the connecting sender; DMARC uses alignment to connect authentication results to the visible author domain.
Find the policy
Look for a TXT record beginning with v=spf1 at the domain used for the envelope sender. The visible From domain is not always that domain. A diagnostic tool can find policy text, but merely finding the text does not prove a specific message passed SPF. Inspect the recipient’s message authentication results for that evidence.
Repair duplicate policies
Publishing multiple SPF policy records at the same name is not a way to authorize multiple providers. Review all legitimate senders and consolidate them into one policy using the providers’ documented mechanisms. Keep unrelated TXT records, such as ownership-verification records; they are not duplicate SPF policies.
Understand lookup complexity
Mechanisms that trigger DNS lookups are subject to SPF evaluation limits. A short-looking policy can still expand into many lookups through included providers. The Login2Cloud presence/count checker does not claim to recursively evaluate every mechanism or certify compliance with every SPF limit. Use provider diagnostics for a specific sender and inspect real delivery evidence.
Change and verify
Record the old policy, make the smallest correction, and allow for DNS caching. Send controlled messages through each legitimate source. Verify SPF, DKIM and DMARC outcomes at a receiving mailbox before tightening enforcement. Keep a list of sending services so future migrations do not leave stale authorizations.
Common questions
Is one SPF record enough to guarantee delivery?
No. A single policy may still be incorrect, and receivers consider many signals beyond SPF.
Should I delete all other TXT records?
No. Only consolidate duplicate SPF policies after reviewing their purpose. Other TXT records can be necessary.