Glossary
Email authentication
Alignment
The requirement that the domain authenticated by SPF or DKIM match the domain in the From header. A message can pass SPF or DKIM and still fail DMARC because the passing domain was not the one the reader sees.
Defined in RFC 7489 §3.1.
Where this appears
The lessons that use this term, and what each is for.
Email Authentication FundamentalsWhat alignment meansGiven a message’s three domains, decide whether DMARC will consider it aligned.Email Authentication FundamentalsRelaxed and strictChoose an alignment mode for a domain and defend the choice against its failure cases.Email Authentication FundamentalsForwarding, mailing lists, and the limits of each protocolPredict which of SPF and DKIM survives a given intermediary, and why.SPF PractitionerGetting a vendor to alignConfigure a custom return-path so a platform’s mail aligns under relaxed mode.SPF PractitionerWhen a vendor cannot alignDecide between a sending subdomain, DKIM-only alignment, and dropping the vendor.SPF PractitionerResults that look impossibleExplain a pass that was rejected, and a fail from a host you know is authorised.DKIM PractitionerGetting d= alignedTake a vendor from signing as themselves to signing as you, and verify it happened.DMARC PractitionerFour causes, one methodTake a failing message to one of four causes using only its headers.DMARC PractitionerForwarding and mailing listsSeparate the mail you can fix from the mail nobody can, and say which is which.Email Security PractitionerThe work that is not yoursIdentify every party whose action the programme depends on, before you commit to a date.Email Security PractitionerA sending account that is not yours any moreRespond to a compromised platform account that is sending authenticated mail as you.Email Security PractitionerHolding a vendor to itGet a specific alignment commitment from a sender, or establish on the record that they cannot meet it.Email Security PractitionerFraud that authenticates perfectlyExplain why the most costly email fraud passes every check you have deployed.Email Security PractitionerA worked estateTake a fictional estate from cold audit to enforcement, making every decision explicitly.