Email DNS check
Check the DNS records that decide where a domain’s mail is delivered and whether its messages are trusted: MX, SPF, DKIM and DMARC, plus MTA-STS, TLS reporting and BIMI.
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The records
- MX tells other servers where to deliver mail for the domain. When you move to a new email host, this is the record you change last.
- SPF (a TXT record starting v=spf1) lists the servers allowed to send as the domain. Only one SPF record is allowed, and it may cause at most 10 DNS lookups, counting every include: inside it.
- DKIM publishes the public key that verifies the signature your mail server adds to each message. It lives at selector._domainkey.domain; the selector is in the s= tag of the DKIM-Signature header of a message you sent.
- DMARC (at _dmarc.domain) tells receivers what to do when a message fails both SPF and DKIM for the From domain: nothing (p=none), spam folder (quarantine) or refuse it (reject), and where to send reports.
After an email migration
When you switch hosts, add the new provider’s SPF include and DKIM key before changing MX, then remove the old provider from SPF once mail flows through the new one. Leaving both can push SPF over 10 lookups; removing the old one too early bounces mail still sent from it. See the guides for the steps per provider.
Why DKIM can show “not found”
Selectors are chosen by each provider and can’t be listed from DNS, so without one we try the common names (default, google, selector1, selector2, k1 and others). If your provider uses a different one, enter it above.
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