E-Mail

E-mail travels across the Internet in small packets, just like any other piece of information. The packets travel from mail server to mail server and are reassembled at the destination and delivered to the addressee's inbox. The path is decided using SMTP (Simple Mail Transfer Protocol). Mail messages are stored on the mail server, not on the user's local machine.

A program called a Transport Agent is responsible for ensuring that your mail is sent correctly via SMTP. The Transport Agent is running on your ISP/online service's mail server. Therefore, you do not have a Transport Agent running on your computer, but your online service or ISP has one running on its mail server.

The transport agent has to be up and running 24 hours a day, ready to accept your mail as it arrives. Once the mail arrives, the Transport Agent saves it in your mailbox. Therefore, when you connect to Internet, your mail is waiting for you to download.

You communicate with the mail server via POP or the Post Office Protocol. So, SMTP is responsible for sending mail over the Internet and POP is responsible for delivering mail from the mail server to you and transporting the mail from your computer to the server.

If you're using Hotmail or Yahoo Mail, you will likely use HTTP when you connect to the service, send your messages to the mail server, and when you receive your Email messages over the Web.

An email message consists of two major parts: the message header and the message body.

Parts of the header:

From: Who sent you the message
Return-Path: Tells your mail program where mail should be sent if the user chooses "reply"
Received: Traces the route the E-mail message traveled.
Date: Shows the date and time the message was sent. If there is a minus sign after the time, this means that the sender’s local time is this amount less than the time in GMT or Greenwich Mean Time. Greenwich, in England, as you know, is 0 degrees longitude.
Message ID: Every E-mail message has its own unique ID. No two Ids will ever be the same.
X-Mailer: The name of the client program the E-mail message was created on.
To: Who the recipient of the message is
Cc: Who else is receiving a copy of the message
Subject: What the message is about

The body is what you would expect it to be, the actual message.

Sending an Email

The To Line: The recipient's email address. If you are writing to someone on the same network, you can leave off every part of the address except for the user name. For example, I can write an email to jsmith@cs.com while I'm logged into Compuserve by typing 'jsmith' on the To line.

The From Line: It's not necessary to fill out the from line because your real information will be sent no matter what you type.

The Subject Line: If the user doesn't know your email address, he/she may not read your email thinking it is Spam unless the subject line of the message clearly indicates that it's from you (Hello from Steve Schwarz). Also, if the email message is urgent, you should indicate so on the subject line. At worst, the subject line should contain a summary of what the message will be about (meeting summary from last week)

CC And BCC: The difference between the two is that blind carbon copy recipients are not visible to any of the other recipients, including other blind carbon copy recipients.

Attachments

Because of the way the Email system is set up, you can only send plain text messages using SMTP. When you need to send a file that is not plain text over the Internet, the file is sent as an encoded attachment to the mail message. The attachment is encoded using MIME (Multipurpose Internet Mail Extensions)

The subject of a mail message should indicate that an attachment is included. You can attach more than one file to an email. Some online services only allow one file to be attached to a message. Additionally, some online services limit the size of the attachments. To get around these issues, you should utilize compression software such as Winzip that allow you to shrink and store multiple files as a single file with a .zip extension.

Signature Files

If you have ever gotten tired of signing your name and job title to the bottom of many an email message, than a signature file is for you. You can instruct your email program to insert the signature file into every message automatically. Signature files often include home address, fax number, phone number, and the sender's favorite quotation or saying. Using a signature files with the above information will guarantee that the recipient will be able to contact you using a variety of methods.

Make sure your signature matches the tone of most of the email that you send using your account. If you care to include a signature on a business account, make sure the tone of the signature file isn't too informal. Some businesses require that all employees follow a standard signature format (Figure 2-3)

You should also try and keep your signature file short and sweet. It is in poor taste to have a really long signature file.

E-mail Addresses

Email address follow the format username@hostname. To repeat, the hostname can be left off if the recipient is on the same network as the sender.

Summary of How Email Works

You compose email (online or offline)
You hit the send button (online)
Mail travels via SMTP (Simple Mail Transfer Protocol)
Mail arrives at ISP's or network's mail server.
Mail server's transport agent contacts recipient's mail server.
Mail is transferred via SMTP to recipient's mail server.
Mail is stored in recipient's inbox.
Recipient goes online to get mail. Mail transferred via POP (Post Office Protocol)
If they reply, the process begins again.