Basic & Extended Smtp Mail Server Commands

By Author: devis eliot
Total Articles: 37
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Searching for a pen and paper to drop a line to your near and dear ones has become history of yesteryears. In recent technological era, when life is so busy, there is hardly any time for an individual to keep on waiting for the replies to their letters as it was observed in earlier times. Nowadays, everyone want everything to be at their fingertips. In such a scenario, email facilities, efficiently driven with the help of SMTP mail server, is considered as the most effective tool used for both personal as well as professional communication. With the help of electronic mails, the people get an opportunity to experience an instant communication process without any delay. Delays are only observed when the SMTP service is not properly installed within the user's system.

For proper conduction of the emailing process, however, a set of commands is there that is followed by the SMTP mail server. Some of the basic as well as extended commands have been discussed below:

Basic SMTP mail server commands:

HELO: Identifies the sender or client to the SMTP server.
MAIL FROM: This ...
... command is used to specify the email address of the sender.
RCPT TO: This SMTP mail server command specifies the recipient's email address.
DATA: It triggers the action of transferring the actual mail data consisting of the body text and attachments, etc.
RSET: Conveys the abortion of the current mail transaction that is taking place.
VRFY: This SMTP mail server command verifies and confirms that the user or mailbox that has been specified is valid and genuinely exists.
HELP: This is used to send useful information or details to the client.
QUIT: It, simply, quits the entire emailing session.

Extended SMTP mail server commands:

EHELO: It acts in the same way as HELO command, but in addition, it also conveys the server that the client wants to use extended mail server protocol.
AUTH: This is the command that authenticates the client to the server. As soon as the user name and password is entered, it is this command which sends the same to the server.
STARTTLS: It stands for Start Transfer Layer Security. While sending the messages, sometimes, the routers that are used may not be controlled or trusted by either the client or the server. With the help of this SMTP mail server command, the communication or email transaction procedure can easily be monitored along with the provision of altering the messages to be sent through the routers. Using this command, however, along with AUTH can be the best and most secure way to authenticate the users.
SIZE: This command specifies the maximum size of the message that a sender can send and the same command specifies the size of content that the recipients can receive.
HELP: This SMTP mail server command is used in the same way as specified under the basic command classification.

With the help of the SMTP service available, the clients send these commands to the mail server, in return to which the server replies in terms of numerical codes followed by text messages separated by a space character. Through these messages, the clients come to know whether the commands used previously have worked successfully or have failed to work properly.