E-mail has become a key part of the communications networks of most modern offices. It is one of the best application of a computer science. The most popular email is Gmail Data and massages can be transmitted from one computer to another using telephone lines, microwave links, communications satellites, or other telecommunications equipment. The same message can be sent to number of different addresses, forwarded and replied to. E-mail is send through company's own local area network and beyond, through a worldwide communication networks like Internet.
Email services typically store messages at a central location called servers from where the messages can be downloaded by a receiver, after logging into his/ her mailbox (Inbox). The client or receiver of the email message, uses typically a browser based application like GMail, Facebook, Twitter etc to open up and sign into his email box. ( All these e-mail services are free, you just have to register or sign up yourself and get started immediately). Thus the message is routed to the destination using telephone cables, wireless network etc. With a subscription to a public e-mail network, an individual PC user needs only a modem and a telephone to send and receive text or vocal messages (Voice mail). Because of the huge amount of e-mail that can be generated, systems have been developed to screen mail for individual users ( to prevent Spam Messages).
Various standards have been devised for exchange of emails. Sites on the Internet adhere to one laid out in RFC 822, augmented by some RFCs that describe a machine-independent way of transferring special characters. Much thought also have been given recently to "multi-media mail", which deals with including pictures, music and sound and videos the e-mail messages. Another standard, X.400, has been defined by CCITT.
Basics of Sending and Receiving
To send and receive electronic-mail messages, or e-mail, over the internet, and to organize your messages, you need an e-mail account. You can get this through an Internet Service Provider ( ISP) in your area. These days companies like Google, Rediff, Facebook, Yahoo etc are providing free email accounts for personal and company use. You also need an e-mail client , an e-mail software ( which also you get free from above companies). Your e-mail client creates an inbox for you and also provides interface for composing and organizing ( delete, archive etc) your mail messages.
Whatever program you choose, you will typically need to set the SMTP server ( Only when you are using your personal client, no such headaches when you use GMAIL, HOTMAIL, YAHOO MAIL etc). This is your ISPs server , through which you send e-mail. Your ISP can tell you the name and address of your SMTP server.
How e-mail looks like
Each mail message you send or receive consists of two parts, the header and the body. The body is straightforward. This is where you write what you want to write in a letter. The header consists of address of the receiver , who should get the carbon copy, whether anything is attached to the mail message ( you can attach files as an attachment).
The email header contains From: and To: addresses and the subject and date of the message as well as other, sometime cryptic information. This information is in a standardized format because it must be interpreted by software responsible for routing the e-mail to the destination.
Th email body : It consists of Message you write. Sometimes the body will contain few other things. For example, if the e-mail has been forwarded or returned after being replied to, the beginning of the body will be the header of the forwarded or returned piece of mail. Also the body, will sometimes contain an attachment. With the advent of MIME, the multipurpose Internet mail extensions standards, the body of an e-mail message can even contain encoded pictures and audio.
People often append a "signature" to the body of their e-mail. This makes it easy for the recipient to find information on the sender, such as return e-mail address. A signature can be very useful because the From: address in the header can be garbled by some mail-forwarding software. This is especially true for people who send e-mail to the Internet via some other connected network or the UUCP data-transmission protocol.