Glossary
Email authentication
Mechanism
A term in an SPF record that can match the sending IP — ip4, ip6, a, mx, include, exists, ptr, all. Mechanisms are evaluated left to right and the first match decides the result.
Defined in RFC 7208 §5.
Where this appears
The lessons that use this term, and what each is for.
Email Authentication FundamentalsThe shape of an SPF recordFind a domain’s SPF record and break it into its terms.Email Authentication FundamentalsMechanisms and evaluation orderPredict the SPF result for a given sending IP against any record.Email Authentication Fundamentalsinclude, redirect, and nested recordsTrace an SPF evaluation through nested includes and say where it stopped.SPF PractitionerThe algorithm, term by termWalk any evaluation in the order a receiver walks it, and say where it stopped.SPF PractitionerMacro syntaxExpand any SPF macro by hand for a given connection.SPF PractitionerWhat macros are actually used forRecognise a per-IP authorisation scheme and say what its DNS backend must do.SPF PractitionerWhat mx and a really costSay what a single mx term costs on a domain with five mail hosts, and why.SPF PractitionerFlattening, mechanicallyFlatten a record correctly, and state the monitoring it now requires.SPF PractitionerDynamic SPFExplain how an exists-based record answers per connection, and what it demands of DNS.