Some basic command tables for the SMTP protocol

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???? When testing the mail server, you need to use the SMTP protocol to log on to the server side, e-mail sent to test to verify that the e-mail server is configured correctly. The following paragraph is an example of sending a short email using the telnet login mail server:

#telnet localhost smtp#mail from:[email protected]#rcpt to:[email protected]#dataHi, Bob!        This is test email!.#quit

???? In the above code block, mail from, RCPT to, data, and quit are all SMTP directives. The basic SMTP instruction set is as follows:

Command	function
HELO	Identify user identities to the server
MAIL from:	Message transfer Source Address
RCPT to:	Indicates the recipient of the message.
DATA	You will enter the message body
Vrdy	Used to verify that a user/message exists (This command is often forbidden)
EXPN	Verify that the mailbox list is present (This command is often forbidden)
Help	See what commands the server supports
NOOP	No action, server response OK
QUIT	End the answer.
RSET	Reset the reply, the current transfer is canceled

Some basic command tables for the SMTP protocol