Email standards

Email structure

These RFCs define the way emails themselves are structured.

Email protocols

These RFCs define how emails are transported between computers, both for sending (SMTP) and receiving (IMAP/POP).

Email security

These RFCs define some security standards for email protocols and formats.

Service discovery

Email software, including clients like Outlook and Mac Mail, need to know which mail server to contact in order to download the user's messages. This used to be manually configured by the user, but nowadays is often done by putting the user's email address through a service discovery process.

Some software vendors maintain their own database of links between email domains and server name definitions to support automatic configuration in their email clients. These seem to be custom databases maintained by each software vendor separately.