Communication Technologies - Email

E-mail

E-mail, or email, is an abbreviation of Electronic Mail. Wikipedia (2004) suggests that e-mail is an instantaneous method of composing, sending, and receiving messages over electronic communication systems – predominantly the Internet.

Developed in 1965, e-mail pre-dates the Internet. First developed as a means of communication between multiple users of a single time-sharing mainframe computer, e-mail has today evolved into one of the world’s most prominent means of communication, with billions of e-mails messages moving across the Internet every year. No longer restricted to simple text messages, e-mail is now capable of sending complete data files, images, and messages including sound, and video.

An e-mail is sent in 5 steps.

1. Message Sender. The message Sender uses a Mail User Agent (MUA) or webmail service to compose a message. The e-mail address of the intended recipient is entered and the e-mail is sent. System software – also known as Transmission Control Protocol (TCP) – divides the message into packets and adds information regarding how each packet should be individually handled, such as the order in which they were sent. Packets are then sent via the MUA using Simple Mail Transfer Protocol (SMTP) to the local Mail Transfer Agent (MTA) – which is typically run by the Internet Service Provider (ISP). Webmail can be used as an alternative to MUA; and the computer in use may already have its own MTA, thus eliminating the need to send the packets to it.

2. Internet Mail Address. The MTA detects the destination address – text preceding the @ symbol denotes the local part of the address, while the text following the symbol denotes the domain name.

3. Mail Transfer Agent. The MTA converts the domain name of the recipient’s address into a numeric Internet Protocol (IP) address by querying domain name servers spread throughout the Internet. The MTA looks up this domain name in the Domain Name System (DNS) to find the mail exchange servers accepting messages for that domain. The DNS responds, listing the mail exchange servers for the domain, and the correct IP address is attached to each message packet (SeniorIndian.com 2003).

4. Routers. Routers throughout the Internet read the IP address on a packet and relay it toward its destination on the most efficient path by using SMTP.

5. Destination Mail Server. The Destination Mail Server - usually a Post Office Protocol (POP) server - places the received packets in their original order according to the instructions contained in each, and stores the message in the recipient’s mailbox. The recipient’s client software can then display the message.

Increasingly, the effectiveness of e-mail is being threatened by spamming and e-mail worms. Wikipedia (2004) suggests that spamming is ‘unsolicited commercial e-mail’ that can be sent inexpensively to multitudes of e-mail addresses with very little effort; while worms use e-mail as a way of replicating themselves into vulnerable computers. The combination of the two results in e-mail accounts constantly receiving junk e-mail, thus reducing the usefulness of e-mail as a practical tool.

List of References

E-Mail – How Does It Work? 2003. SeniorIndian.com Web site: http://www.seniorindian.com/email.htm (accessed October 27, 2004).

Electronic Mail. 2004. Wikipedia Web site: http://en.wikipedia.org/wiki/Email (accessed October 27, 2004).

Melissa Patch 02:23, 29 Oct 2004 (EST)