SPF, DKIM & DMARC checker
Look up what receivers see for your domain: MX, SPF (with the 10-lookup count), DKIM selectors and DMARC policy — and exactly what to add.
Why these three records decide inbox vs spam
- SPF — a TXT record listing the servers allowed to send for the domain. Limited to 10 DNS lookups across all includes; more than that is a permerror.
- DKIM — a public key at
selector._domainkey.domain; the sending server signs each message with the private key. Alignment with the From domain is what DMARC checks. - DMARC — the policy telling receivers what to do with mail that fails alignment (none / quarantine / reject) and where to send aggregate reports. Required by Gmail and Yahoo for anyone sending 5,000+ messages a day, and strongly recommended for everyone.
Setup walkthrough: SPF, DKIM & DMARC setup guide. Provider-specific includes and selectors: SMTP settings hub.
Records generated for you
Add a domain in QueenSMTP and the dashboard shows the exact SPF include and DKIM record, then verifies them live before your first send.
Verify a domain — freeSPF, DKIM & DMARC — questions
SPF lists which servers may send for your domain; DKIM signs each message so receivers can verify it was not altered and really came from you; DMARC tells receivers what to do when SPF/DKIM fail and where to send reports. Gmail and Yahoo require all three for bulk senders since 2024.
Receivers stop evaluating an SPF record after 10 DNS-querying mechanisms (include, a, mx, ptr, exists, redirect) counted across all nested includes; beyond that SPF returns permerror and fails. Flatten or remove includes to stay under 10.
Open a message you sent in Gmail → "Show original": the DKIM-Signature header has s=