Electronic mail (email) was created to allow two individuals to communicate using computers. In early days, the e-mail technology allowed one person to type a message and then send it to another person over the internet. It was just like a posting a letter, except the communication was electronic, instead a paper.
Features of Electronic Mail
1. Composing and sending/ receiving a message.
2. Sending a single message to more than one person.
3. Sending text, voice, graphics and video etc.
Functions Performed by Electronic Mail
Electronic mail uses TCP/ IP as the underlying protocol. This means that when a person X write a message to Y, it is broken down into packets according to the TCP/ IP format, routed through various routes of the Internet and reassemble as the complete e-mail message at the destination before it is presented to Y for reading.
An email mailbox is just a storage area on the disk of the computer. This are is used for storing received emails; similar to the way a postal mailbox stores postal mails. The computer who is given responsibility of storing email messages centrally along with the software is called email server. The email server is dedicated to its task of storing and distributing emails, but can, in theory, also perform other tasks. There is a mailbox (i.e., some disk space) on the email server computer for each client computer connected to it and wanting to use the email facility. That server is to be kept constantly.
All mails received for all the users connected to the server are received and stored on this server first. The reason is that it is always on.
Electronic Mail Software
The email software has two parts. One that runs on the client (user’s) PC known as email client software and the other that runs on the email server, called to email server software. For writing email, the sender runs email client software. This software is a program that allows the user to compose an email and specify the intended recipient’s email address. Using the recipient’s email address, the email travels from the source to the email server of the source and then to the recipient’s email server – of course through many routers. As we know, again the undergoing protocol is TCP/ IP. This means that the bits in the contents of email are broken down into packets as per TCP/ IP format and reassembled at the recipient’s end.
Each electronic mail box on the server has a unique email address. This consists of two parts. The name of the user and name of the domain. The @ symbol joins them to form the email address as shown below
The following figure shows the email servers
In email messaging, every domain has email server computer set up. These email servers run protocol software that enables email communication. There are two main email protocols: POP and SMTP. POP is concerned with the retrieval of an email message stored on a server computer, whereas SMTP is actually responsible for transmitting an email message between the sender and the recipient. Because both the email protocol software programs run on server computer, the server computer themselves are known as POP server and SMTP server respectively.