POP3 is an open Internet standard. Login with a username. If valid username, server will respond with request for password. If valid, server response will be two numbers, message count and mailbox size. Get the mailbox status.
Response is two numbers, message count and mailbox size.
Get list of messages. Needed in unusual programming situations. Commits all changes, unlocks the mailbox, and ends the server connection. Useful on low bandwidth lines to get just the first part of long messages. The current version is IMAP4, and provides similar services to the POP3 protocol, but includes additional features such as the ability to keep your email on the server after downloading a copy to read locally.