Simple Mail Transfer Protocol (SMTP) is the most widely used standard for sending and receiving email.
Most email systems that send email over the Internet use SMTP to send messages from one server to another server. The messages can then be retrieved with an email client using either Post Office Protocol (POP) or Internet Message Access Protocol (IMAP).
Most email systems that send email over the Internet use SMTP to send messages from one server to another server. The messages can then be retrieved with an email client using either Post Office Protocol (POP) or Internet Message Access Protocol (IMAP).