Email DNS and SPF checker

Inspect MX, SPF, DMARC, DKIM, MTA-STS, TLS-RPT and BIMI without connecting to a mail server.

Queries are sent from NekoIP infrastructure. The target website is not contacted.

What do you want to do?

Choose a task. Only the fields needed for it will be shown.

Choose whether to check a domain, inspect DKIM or create a policy record.

Analyze domain No connection is made to the mail server.
Optional settings Add it only when you want DKIM checked, for example default.
Examples:

Result

Enter a value to see the result.

What this tool checks

The check reads MX and public TXT policies for SPF, DMARC, DKIM, MTA-STS, TLS-RPT and BIMI. It never opens SMTP, downloads an MTA-STS policy or guesses DKIM selectors.

How to read the result

Review MX delivery first, then SPF lookup and void limits, DMARC policy and percentage, and each auxiliary policy. A valid TXT syntax does not prove that mail delivery or reporting works end to end.

Common problems

Multiple SPF or DMARC records, more than ten SPF DNS terms, unknown DKIM selectors and premature DMARC reject policies are common causes of mail failures.

Command-line example

dig example.com MX; dig example.com TXT; dig _dmarc.example.com TXT

Related guides

DNS record types explainedA practical map of the DNS records used by websites, mail and domain security. SPF syntax and the 10-lookup limitUnderstand SPF mechanisms, recursive includes, void lookups and permanent errors. DMARC policies and tagsHow alignment, reporting and p=none/quarantine/reject work together. DKIM, MTA-STS, TLS-RPT and BIMIThe DNS records that complement SPF and DMARC for modern mail domains. EPP domain status codesTranslate registry statuses such as clientTransferProhibited and redemptionPeriod. RDAP versus WHOISWhy structured RDAP is preferred and when a controlled WHOIS fallback is useful. CIDR and subnet-mask cheat sheetA durable reference for IPv4 prefixes, host counts, wildcard masks and subnet planning. Private and reserved IP rangesDistinguish private, loopback, link-local, documentation and globally routable addresses. Reverse DNS and FCrDNSHow PTR lookup and forward-confirmed reverse DNS are used in operations and email. IDN, Punycode and mixed-script domainsRead internationalized domain names safely without treating every non-ASCII label as suspicious.