Electronic mail, better known as email is a process of exchanging messages digitally. In this process messages are stored and forwarded through different storage servers. In these servers email data is stored and fetched when required. Read this article to know more.

An email has two parts: the header and the body. The header contains important information like sender's address; time email was sent and delivered etc.

Email initially was just a text message but gradually with improvement in technology attachments became a part of emails too. It's a day of the past where email messages had a meager size limit of a few kbs but now messages of more than 10 mb can be sent.

Now let's find out what email clients are. There are different standalone email clients like MS Outlook, Outlook express, Thunderbird, Seamonkey etc. On the other hand there are web based email clients like Hotmail, Gmail, and Yahoo etc. But which ever email client you use the tasks performed are overall the same.

• Shows you a list of all of the messages in your mailbox by displaying the message headers. The header shows you who sent the mail, the subject of the mail and may also show the time and date of the message and the message size.
• Lets you select a message header and read the body of the e-mail message.
• Let's you create new messages and send them. You type in the e-mail address of the recipient and the subject for the message, and then type the body of the message.
• Lets you add attachments to messages you send and save the attachments from messages you receive.

Now that we have learnt about email clients, let's find out what else is required for the complete functioning of the process. The most important of all without which emails will not work is the Email Server for the clients to connect to.

There are different servers for different purpose. POP/POP3, IMAP servers handle incoming email, SMTP server handles outgoing email.

POP stands for POST OFFICE PROTOCOL and IMAP stands for INTERNET MESSAGE ACCESS PROTOCOL.

There are certain differences between POP/POP3 and IMAP server, the way these servers operate. Both have their own pros and cons.

• POP3 always downloads all new emails locally to your computer.
• IMAP downloads message summaries and doesn't download the entire message until you want it to.
• POP3 downloads all emails into 1 mail folder called "Inbox".
• IMAP preserves your folder structure in a main folder called "imap.*.com".
• POP3 is useful if you only access your email from one computer, since the email is typically downloaded locally (this is the default and can be changed).
• IMAP allows email to be manipulated from a desktop computer at home, a workstation at the office, and a notebook computer while traveling, without the need to transfer messages or files back and forth between these computers.
• With POP3, your emails can be automatically erased from the server after they are downloaded freeing up space in your account.
• IMAP keeps all emails on the server until you erase them.

Now let's throw some light on the SMTP server. Let's find out what it is and its functions. SMTP stands for SIMPLE MAIL TRANSFER PROTOCOL. SMTP is used for delivering emails to the recipients email address. It is used in conjunction with a Pop/Pop3 or IMAP server. Email clients use either a POP3 or IMAP along with SMTP; else mails will be received only but not send.

The last protocol is the HTTP which stands for HYPER TEXT TRANSFER PROTOCOL. This is not a protocol which is dedicated for email communications though it can be used to compose or retrieve mails. This is also called web based email.

The last one is the usage of MS Exchange for email clients like OUTLOOK. This is used in corporate environments only using MS infrastructure solutions. Its major features include email, calendar, contacts and tasks etc. It also can be synched to a hand held device or a mobile. It also supports data storage.

MS exchange has come a long way with its different versions starting with Exchange 1.0 and now the most recent MS Exchange Server 2010.