Mail Transfer Agents

An autoresponder is a computer programme that automatically answers any e-mails that are sent to it. They can be either extremely simple or indeed quite complex.

The first autoresponders were establishted by way of mail transfer agents. Such devices found they were unable to deliver an e-mail to a particular address. The result of this failure to deliver was the creation of bounce messages, such as "it was not possible to deliver your email because..." type responses.

The internet's uses a standard e-mail protocol called SMTP (or Simple Mail Transfer Protocol which is designated as the Internet standard for electronic mail (e-mail) transmission across Internet Protocol (IP) networks). A bounce message takes the form of an automated email message from a mail system. The nature of the message is to inform the sender that there is another message concerning a problem related to the delivery of their message. In this way, the original message is said to have bounced. Today’s autoresponders need to pay particular attention to the avoidance generating e-mail backscatter. By not avoiding this simple precaution, the autoresponses may be regarded as just another form of E-mail spam.

Email spam, viruses and worms represent damaging outcomes related to backscatter. It is caused by e-mail servers receiving spam and other mail. As a result of this, bounce messages are sent to innocent third parties. The cause of this is that the original message envelope sender is forged to contain the usually unprotected e-mail address of the victim. In nearly all cases, such e-mails are dispatched with a forged From: header, almost identical to the envelope of the sender.

A mail transfer agent (MTA), also known as a message transfer agent, is in fact a computer process whereby electronic mail messages are transferred from one computer to another in the form of single hop application-level transactions. An MTA is handles the client (who is sending the message) as well as the server (which is at the receiving end) elements of the Simple Mail Transfer Protocol.

Mail is transferred from one MTA to another, and the details involved in the transmission are notified by the SMTP. On those occasions when the recipient of a given message is not hosted locally, the message is forwarded to another MTA. Whenever an MTA receives an email message, it automatically adds a Received trace header field to the top of the headers of the message. In this way, there is an established build-up of sequential records of MTAs handling that particular message.

The MTA continues working in the background, whereas the user normally interacts by way of a mail user agent, or MUA (which is a computer program for the purpose of managing emails). For message recipients that are hosted locally, the message delivery agent, or MDA, is responsible for ensuring that the email is delivered to the recipient’s mailbox. The MDA is computer programme that transfers the responsibility for the management of e-mail messages from the MTA within the message handling service, or MHS, to a recipient's environment, most notably transferring them into a mailbox. In this way, the message handling segment of the message delivery agent (MDA) receives the message from the MTA. Once the delivery of the message has been finalised, the Return-Path field is added to the envelope to record the return path.

Autoresponders – How To Succeed

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