Internet Message Access Protocol, a standard protocol for accessing email from a server.
Post Office Protocol, which an email client uses to send to or receive messages from an email server.
Domain-based Message Authentication, Reporting and Conformance (DMARC) is an email authentication protocol to help protect a domain from spoofing. It allows the domain owner to specify deliverability policies and receive reports on messages sent „from“ this domain that fail authentication. It requires that DMARC and SPF are aligned with the message’s „From:“ domain.