What Domain Check tests
Five checks: the ones every server that receives an email in your name looks at. Each one carries a weight in the score according to its role in protecting your domain.
MX servers
Do the servers that receive your email exist, and are they declared correctly? 10% of the score. The MX check in detail
SPF
The list of servers allowed to send on your behalf, its syntax and the 10 DNS lookup limit. 25% of the score. The SPF guide
DKIM
The signature on your emails, across some sixty common selectors, with the exact key length. 25% of the score. The DKIM guide
DMARC
The instruction given to recipients when an email spoofs your domain, and the reports you ask for. 30% of the score. The DMARC guide
Blacklists
The IP addresses specific to your mail servers (excluding providers with shared addresses), checked against five public lists. 10% of the score. The lists queried
100% in your browser
The analysis only reads public DNS data, the same data any mail server looks up. It runs entirely on your device.
No data kept
The check does not send the domain you enter to SF2i. Your browser queries the public DNS resolvers of Cloudflare directly and, as a fallback, those of Google.
No cookies
No cookies, no local storage and no audience measurement. So there is nothing to accept before you run the test.
A report to pass on
The PDF report is produced by your browser. You can pass it on to your IT provider or your management, if you wish.
A score that is explained
Weighting, caps and "not verifiable" cases: the whole calculation is published on the Method page.
Understand and fix
Every finding in the test leads to an action. These guides explain the role of each record and how to set it up for Microsoft 365, Google Workspace or any other provider.
Frequently asked questions
Is the test free?
Yes. Domain Check is a free tool from the SF2i group, with no sign-up and no account. You can check as many domains as you need and save the PDF report.
Is my data kept?
No. The analysis runs in your browser, using the domain's public DNS data. The domain you enter is only sent to the public DNS resolvers of Cloudflare and, as a fallback, Google: SF2i does not receive it and keeps nothing. The site sets no cookies and uses no local storage or audience measurement.
How is the score calculated?
Each check receives a score out of 100. The overall score is their weighted average: DMARC 30, SPF 25, DKIM 25, MX 10 and blacklists 10. An SPF record ending in +all or a blacklisted IP address caps the score at 49. A point that cannot be verified is left out of the calculation, and the score is then flagged as partial. A score of 80 or more is good, 50 to 79 needs improvement and below 50 is critical. Every rule is set out in detail on the Method page.