DNS & EMAIL
SPF Record Checker
Find the domain’s SPF TXT record and highlight common configuration problems.
39DExternal testRuns from the 39D platform
RUN TEST
SPF Record Checker
HOW IT WORKS
About the SPF Record Checker
SPF identifies which systems may send mail using a domain in the SMTP envelope. The checker finds records beginning with v=spf1 and performs basic structural checks, including multiple-record and DNS-lookup warnings.
How to use this result
- Run the test from this server.Use a public hostname, address, prefix or ASN in the format requested above.
- Compare test locations.Choose another available 39D node or run a local command to identify location-specific behaviour.
- Correlate related evidence.Use the related tools below to compare DNS, routes, ports, TLS and application responses.
- Keep the time and context.Routing, DNS caches and reputation data change, so record when the result was collected.
Common interpretation issues
- A domain must not publish multiple SPF records.
- Too many include, a, mx, ptr, exists or redirect lookups can exceed the SPF limit.
- SPF alignment for DMARC depends on the envelope domain, not only the visible From address.
NEED HELP INTERPRETING THE RESULT?
39D supports business networks, cyber security and managed IT.
For ongoing support or a larger infrastructure project, speak to the 39D team.
Frequently asked questions
Should I use -all or ~all?
Use a policy that matches your deployment and test carefully before moving to a hard fail.
Does SPF protect incoming mail?
It helps receivers evaluate mail claiming to come from your domain.