Glossary. The email-authentication vocabulary, in plain English.
12 guides in this section of the Knowledge Base. For the concepts first, start with Learn.
No guide in this section matches that. The other sections are linked above.
Every guide. In one list.
12 guides- What is the Return-Path? (envelope from)The hidden envelope address that takes your bounces and decides SPF.
- What is the Header From address?The From line people read, why anyone can write anything there, and how DMARC anchors to it.
- What is a DKIM selector?The s= label that names the DNS record holding a DKIM key, and why each vendor gets its own.
- What is DMARC alignment?Why an SPF or DKIM pass only counts for DMARC when its domain matches the From.
- What is a DMARC aggregate report? (RUA)The daily XML receipts receivers send about mail using your domain, and what is inside.
- What is a DMARC forensic report? (RUF)The per-message failure report almost nobody sends, and why RUA does the real work.
- What is an organizational domain?The registrable root DMARC falls back to, by PSL in RFC 7489 and by tree walk in DMARCbis.
- What is a DMARC record?The TXT record at _dmarc: its tags, the rules that bite, and a safe first record.
- What is a DMARC policy? (p=none, quarantine, reject)What p=none, quarantine and reject each ask a receiver to do with failing mail.
- What does quarantine mean in email?Where p=quarantine mail lands at each receiver, and how it differs from reject.
- What is email spoofing?How anyone can write your domain into a From line, and what lets receivers refuse it.
- What is a Verified Mark Certificate? (VMC)The certificate that proves the logo in your BIMI record is yours, and who needs one.
Start with one domain. See it with your own data.
Free for one domain, no card. Add one DNS record and the first reports usually arrive within a day.