Panasonic DX-2000 Service Manual page 316

10.8.1. Opening and Closing
At the time the transmission channel is opened there is an exchange of commands to ensure that the hosts are communicating with
the hosts they think they are. The following two commands are used in the transmission channel for opening and closing:
HELO:<SP> <domain> <CRLF>
QUIT:<CRLF>
In the HELO command, the host sending the command identifies itself; the command may be interpreted as saying, "Hello, I am
<domain>".
10.8.2 Mail (MAIL)
This command is used to initiate a mail transaction in which the mail data is delivered to one or more mailboxes.
10.8.3 RECIPIENT (RCPT)
This command is used to identify an individual recipient of the mail data; multiple recipients are specified by multiple uses of this
command.
10.8.4 Data (DATA)
The receiver treats the lines following the command as mail data from the sender. This command causes the mail data from this
command to be appended to the mail data buffer. The mail data may contain any of the 128 ASCII character codes. The mail data
is terminated by a line containing only a period, that is the character sequence "<CRLF>.<CRLF>". This is the end of mail data
indication.
10.8.5 Send
This command is used to initiate a mail transaction in which the mail data is delivered to one or more terminals. This command is
successful if the message is delivered to a terminal.
10.8.6. Reset (RSET)
This command specifies that the current mail transaction is to be aborted. Any stored sender, recipients, and mail data must be
discarded, and all buffers and state tables cleared. The receiver must send an OK reply.
10.8.7 Verify (VRFY)
This command asks the receiver to confirm that the argument identifies a user. If it is a user name, the full name of the user (if
known) and the fully specified mailbox are returned.
10.8.8 Quit (QUIT)
This command specifies that the receiver must send an OK reply, and then close the transmission channel.
10.8.9 Reply Codes from SMTP Server
SMTP is independent of the particular transmission subsystem and requires only a reliable ordered data stream channel. The
SMTP design is based on the following model of communication: as the result of a user mail request, the sender-SMTP establishes
a two-way transmission channel to a receiver-SMTP. The receiver-SMTP may be either the ultimate destination or an intermediate.
SMTP commands are generated by the sender-SMTP and sent to the receiver-SMTP. SMTP replies are sent from the receiver-
SMTP to the sender-SMTP in response to the commands.
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