Speak SMTPWhen one sends mail using the SMTP protocol, one has only the following commands:
HELO
Greet the mail server. Used once per session - at the beginning of the session.
MAIL FROM: <from>
Announce who the sender is. Used once per mail, before specifying any recipients for each mail, or after a RSET.
RCPT TO: <rcpt>
Announce who the mail is to. Multiple recipients are allowed, each must have its own RCPT TO: entered immediately after a
MAIL FROM:DATA
Starts mail entry mode. Everything entered on the lines following DATA is treated as the body of the message and is sent to the recipients. The DATA terminates with a . (period) on a line by itself. A mail may be queued or sent immediately when the . is entered. It cannot however be reset at this stage.
RSET
Reset the state of the current transaction. The MAIL FROM: and RCPT TO: for the current transaction are cleared.
QUIT
End the session. No commits happen here.