IMAP / POP3 | Notion

Internet Message Access Protocol (IMAP) or Post Office Protocol (POP3)

POP3 only lets you download and delete emails from the server, while IMAP allows you to organize emails into folders, access multiple mailboxes at once, and manage emails directly on the server.
When a client connects to the server, it uses port 143and sends commands in simple text ASCII format. Multiple commands can be sent at once, and the server will later confirm each one. After connecting, the user must log in with a username and password to access their mailbox, and they can only do so if the login is successful.
IMAP usually sends data like commands, emails, and login details without encryption, meaning it's sent in plain text. To keep things more secure, many email servers use encryption (like SSL/TLS) to protect the connection. This encryption helps prevent unauthorized access. Depending on how it's set up, encrypted IMAP can use the regular port 143 or a different one, like port 993.

Command	Description
`1 LOGIN username password`	User's login.
`1 LIST "" *`	Lists all directories.
`1 CREATE "INBOX"`	Creates a mailbox with a specified name.
`1 DELETE "INBOX"`	Deletes a mailbox.
`1 RENAME "ToRead" "Important"`	Renames a mailbox.
`1 LSUB "" *`	Returns a subset of names from the set of names that the User has declared as being `active` or `subscribed`.
`1 SELECT INBOX`	Selects a mailbox so that messages in the mailbox can be accessed.
`1 UNSELECT INBOX`	Exits the selected mailbox.
`1 FETCH <ID> all`	Retrieves data associated with a message in the mailbox.
`1 CLOSE`	Removes all messages with the `Deleted` flag set.
`1 LOGOUT`	Closes the connection with the IMAP server.

Command	Description
`USER username`	Identifies the user.
`PASS password`	Authentication of the user using its password.
`STAT`	Requests the number of saved emails from the server.
`LIST`	Requests from the server the number and size of all emails.
`RETR id`	Requests the server to deliver the requested email by ID.
`DELE id`	Requests the server to delete the requested email by ID.
`CAPA`	Requests the server to display the server capabilities.
`RSET`	Requests the server to reset the transmitted information.
`QUIT`	Closes the connection with the POP3 server.

Footprinting the Service

By default, ports 110 and 995 are used for POP3, and ports 143 and 993 are used for IMAP.
993 and 995) use TLS/SSL to encrypt the communication between the client and server