--- title: "Domain Authentication Checker | AutoSPF" description: "Check SPF, DMARC, BIMI, MTA-STS, and TLS-RPT records for any domain. Free email authentication audit tool by AutoSPF." image: "https://autospf.com/images/og-default.png" canonical: "https://autospf.com/tools/domain-auth-checker/" --- # Domain Authentication Checker Check SPF, DMARC, BIMI, MTA-STS, and TLS-RPT records for any domain - free. All 5 protocols checked simultaneously - no signup required Enter a domain to check Check All Records Checks SPF, DMARC, BIMI, MTA-STS, and TLS-RPT records simultaneously. Protocol Deep Dive ## 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. Complete Protection ## 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? AutoSPF automatically flattens SPF records and keeps your email authentication aligned. Setup takes 60 seconds. [Start Free Trial→](https://app.autospf.com/login)[View Plans & Pricing](/pricing/) Rated 5/5 on G2 · Trusted since 2018 ## What Our Customers Say ### "AutoSPF Flattens SPF Records Seamlessly & Keeps Changes Logged - I am quite pleased with the product" > It does what it promises to do, and does it very well. I appreciate that it keeps a log of changes made, which prevents many mistakes. A client's SPF record would have way too many lookups, but AutoSPF makes that problem go away. The length of the SPF record is typically not the issue; it's the amount of lookups in the record that are. AutoSPF "flattens" the record, automatically expanding the defined lookups to IP addresses or ranges. And it auto-updates the record when the un-flattened lookups change. PJ Peter J. President · Small-Business (50 or fewer emp.) ### "Helped us go beyond capacity" > AutoSPF did exactly as described, it helped us get past our 10 lookup limit. Afterwards, we hit another limit regarding overall capacity and when contacted, they quickly provided us with a new solution to eliminate capacity issues entirely going forward, so now we can add as many SPF records as needed. They also provided us with a personalized support video explaining their new method in its entirety using our instance as the example. VU Verified User Financial Services · Mid-Market (51-1000 emp.) [Read our reviews on G2 ](https://www.g2.com/products/autospf/reviews) ```json {"@context":"https://schema.org","@type":"Organization","@id":"https://www.wikidata.org/wiki/Q138897474","name":"AutoSPF","url":"https://autospf.com","logo":{"@type":"ImageObject","url":"https://autospf.com/images/autospf-logo.png"},"description":"Automatic SPF flattening and email authentication management. 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