DNS and domains
Online SPF Checker
Analyze a domain’s SPF record, mechanisms, final policy and includes.
SPF guide
What is SPF?
Sender Policy Framework declares which servers are authorized to send email for a domain through a DNS TXT record.
What are includes?
Includes delegate part of a policy to other domains. They are resolved with controlled depth and cycle detection.
The 10 DNS lookup limit
SPF limits mechanisms that generate DNS queries to prevent expensive evaluations. Includes, a, mx, exists, ptr and redirect may count.
SPF, DKIM and DMARC
These are different but complementary technologies. SPF does not replace DKIM or DMARC and cannot prevent every spoofing case alone.
Frequently asked questions
SPF questions
How do I know whether a domain has SPF?
Enter the domain and the tool will find TXT records beginning with v=spf1.
What does v=spf1 mean?
It identifies the SPF1 version of the SPF record format.
What is the difference between -all and ~all?
-all means Fail, while ~all means SoftFail and leaves the receiver more flexibility.
How many includes can I have?
It depends on the complete policy, but generated DNS lookups should stay within the limit of 10.
What happens if I have two SPF records?
Evaluation may fail. The usual approach is to combine the policy into one record.
What does the 10 DNS lookup limit mean?
It is the maximum number of DNS queries an SPF evaluation may generate.
Does SPF prevent spoofing?
It helps validate senders, but should be combined with DKIM and DMARC for broader protection.
Does SPF replace DKIM or DMARC?
No. They are separate mechanisms that complement each other.