DomainKeys Identified Mail (DKIM) is a public key signature system for email domains.
Domain-based Message Authentication, Reporting & Conformance (DMARC) is a policy for emails where both the SPF and the DKIM checks failed.
Mail Submission Agent (MSA) is an SMTP (or API) server that accepts emails for delivery from authenticated users.
Mail Transfer Agent (MTA) is an email server that relays emails between different systems using the SMTP protocol.
Mail Exchange (MX) is the "incoming" email server that accepts emails on behalf of a specific domain name using the SMTP protocol.
Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission.
Sender Policy Framework (SPF) is an allowlist containing IP addresses of email servers authorised to send emails on behalf of the domain.
VERP (Variable Envelope Return Path) is a technique used in email systems to enable automatic tracking and handling of bounce messages. By using VERP, each outgoing email is assigned a unique return path, allowing the email system to identify and process bounced emails more efficiently.