Domain Authentication Checker
Check SPF, DMARC, BIMI, MTA-STS, and TLS-RPT records for any domain — free.
Checks SPF, DMARC, BIMI, MTA-STS, and TLS-RPT records simultaneously.
Understanding Email Authentication Protocols
SPF (Sender Policy Framework)
SPF specifies which mail servers are authorized to send email for your domain. It works by publishing a DNS TXT record that lists approved IP addresses and hostnames. Receiving servers check this record to verify that incoming mail comes from an authorized source.
DMARC (Domain-based Message Authentication)
DMARC ties SPF and DKIM together and tells receiving mail servers what to do when neither authentication method passes — reject, quarantine, or allow the message. It also enables aggregate and forensic reporting so domain owners can monitor authentication results.
BIMI (Brand Indicators for Message Identification)
BIMI lets organizations display their brand logo next to authenticated emails in supporting email clients. It requires a valid DMARC policy (quarantine or reject) and optionally a Verified Mark Certificate (VMC) for logo display in Gmail and Apple Mail.
MTA-STS (Mail Transfer Agent Strict Transport Security)
MTA-STS tells sending mail servers that your domain requires TLS encryption for email delivery. It prevents downgrade attacks and man-in-the-middle interception by publishing a DNS record and a policy file that mandate encrypted connections.
TLS-RPT (TLS Reporting)
TLS-RPT enables receiving mail servers to report TLS connection failures back to you. When combined with MTA-STS, it provides visibility into delivery problems caused by certificate errors, expired certificates, or misconfigured encryption.
Why All 5 Protocols Matter
Anti-Spoofing
SPF + DMARC prevent unauthorized senders from impersonating your domain.
Encryption
MTA-STS + TLS-RPT ensure email is encrypted in transit and report failures.
Brand Trust
BIMI displays your logo in the inbox, increasing recipient confidence and open rates.
Need help fixing your email authentication?
DMARC Report monitors SPF, DKIM, and DMARC across all your domains and shows you exactly what to fix. Setup takes 60 seconds.
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Verified User in Information Technology and Services
"Best security tool for your own domains"
The weekly reports help me a lot to analyze quickly the emails sent from my domains and that gives me peace of mind.
Ryan C.
Director
"Control Centre for Email Security"
I like that we can see and check all reports on just 1 platform. We manage multiple domains, and monitoring them all in one place is essential.
eddy g.
Director
"A great solution to a common email problem."
I have been using them for the last month after my Google business email started giving DMARC errors. I didn't even know what it meant at that time. After a little googling I found that people can spoof it as well. So far so good — the best thing is it protects every email.