SMTP is used to send and receive emails. However, due to its "simplicity," its capacity is limited when queuing messages at the receiving end and is usually used in conjunction with one or two other protocols such as POP3 or IMAP. These other protocols allow users to store messages in the server mailbox and periodically download messages from the server.
SMTP authentication is an extension of SMTP that requires users to log into the mail server before sending or while sending mail. It is used to allow legitimate users to send emails while blocking unauthorized users, such as spammers.
蘊藏許多助人的知識與智慧。