Demystifying and Deciphering the Internet

Brief History


U.S. Military needed a way of sharing and quickly moving data between remote computers to protect the data from nuclear attack. The Defense Department contracted several American universities to develop methods for connecting distant computers and for moving files quickly. This was called the DARPA for

"Defense Advanced Research Projects Agency."


The civilian applications for this quickly became evident as medical researchers used this network to share research data. The program was renamed ARPANET for "Advanced Research Projects Agency Network." ARPANET was the foundation for our present Internet.

1990 to Present

Many companies quickly saw that there were was unlimited commercial potential for this network as the government began to withdraw its control. Soon came private investment and research in the development of an Internet "backbone." This has resulted in the global Internet of the present day.

The Internet

The Internet is a global collection of networked computers. The World Wide Web is the portion that is viewable through Browsers. Other parts are online databases, educational computers, routing systems, email servers, etc.

A large part of this network uses the Telephone system, but it also utilizes satellites, microwaves, infrared, cable, FM signals, cellular networks, fiber-optic cables and a host of other media.


How email works is actually a simpler concept than it may seem at first. On your computer(or actually on a network server or web server) there is a directory called "mail" or "mailbox." This directory is similar to other directories on your computer except for the fact that it is "open" to other clients. Other clients can dump files to, specifically mail messages. Mail messages are similar to other files like Word Documents or Excel Spreadsheets, but they have certain structure designed for email.

The basic email has 4 sections or "fields."

SENDER: This is you and is usually automatically filled for you if you are logged on properly.

TO: This is the receiver and is critical to the processing. The information must be typed correctly to be properly sent. Here at the agency we have two types of recipients: external and internal. For example an internal email might be joesmith and an external might be To send email beyond MHFA you need to have the full address.

SUBJECT: In some email programs this is a required field, in others you may leave it blank. This field to place a one line brief about your message.

MESSAGE or CONTENT: This is the actual text of the message. The three above fields comprise what is know as the "header." The header of the email contains information about the message and how to deliver it, the message is attached to the header.

Other Fields

Cc: "Carbon Copy" an outdated term. Used in email to designate users receiving copies of an email

Bcc: "Blind Carbon Copy." Other recipients cannot see each other.

Attachments: Files attached to emails. Often limited in number and size.

Decoding a URL

http:// - This is the protocol, it is a set of instructions that tells your browser what to get, how to get it and how to display it for you.

www. - Indicates that this can be found on the World Wide Web. In many cases it is not needed.

site - The name of the server or location. Sometimes this is the literal name of a machine, other times it is sub-domain that sits on another machine.

.com - The domain type. Other domain types are: .org for "organization," .gov for "U.S. Government," .mil for "U.S. Military," .edu for "Education institution," .net for a "Network of computers." Each country also has its own code: .ca for Canada, .uk for England, etc. The distinction between .com, .org and .net has become somewhat blurred.

/ - Indicates a sub folder.

information - The name of the file or page.

.html - The type of file being viewed. Sometimes .htm as well. HTML is the code that most web documents are written in. This tells the browser that the file should be viewed as a web page, the same way that .doc tells MS Word to view a file as a word processing document. Other legal types of web documents are .pdf, .txt, .


Browsers are programs(or applications) that allow web documents to viewed. Browsers communicate with web servers through a series of "protocols," rules and instructions. A browser/client first makes a request for connection, the server/host accepts or denies that request and sends its response back to the browser/client. The browser/client then makes a request for a specific document and the server/host replies with a copy of that document.

Netscape an Internet Explorer are the two most popular. There are others, but these are the most widely used and have similar features.

Tool Bar(Netscape)

Back: Return to previous page

Forward: Proceed to next page

Reload: Requests updated version of page

Home: Returns to browser's home page

Search: Links to search engines

Print: Prints current page

Security: Turns on secure browser features

Stop: Stops a page from loading


LYNX is is a text-based browser for web. Designed to be used with non-graphic interfaces it is also a great browser to use if you want to speed your access to content. All you get is the stripped-down text, no waiting for pictures or images to download. LYNX is perfect if you just want to read articles or documentation.

Some LYNX links:
Preview pages in a LYNX browser
Lynx source distribution and potpourri
Lynx for DOS/win32
User's Guide

Search Engines

Search engines are web sites that allow clients to find sites and pages that contain certain information, themes or text.

Select a search engine, type you search terms in the box and click the "Search" button. Depending on the engine this button may be labeled "Go get it,"

"Find it," or "Search."

Narrowing a search

Using Quotes

"This is an exact quote to search for"

Using Boolean Expressions

New AND York NOT City

Avoid common words

"Internet," "cars," "computers," "dogs," etc.

Be specific

Boston stores selling foreign language books

Avoid definite articles and conjunctions

Words like: "the," "in," "but," "or," "and," "at," will get you lots of sites you don't want containing those words or use them as boolean expressions. Be blunt, use "museum" instead of "the museum."

Good Engines






HTTP Response Codes

Code Range

Type of Response

100 to 199

Information for the client about the server

200 to 299

Reports a successfully completed client request

300 to 399

Page or server redirection

400 to 499

Page, server, host not

found/Client request failed

500 to 599

Internal server errors

Codes in the 100 to 299 range are usually never seen by the user and only read by the browser software.

Codes in the 300 to 399 range are sometimes seen briefly while the server redirects the client to another location Codes in the 400 to 599 range are more commonly seen.

400 to 499 usually means that the page no longer exists, an "< A HREF= >" tag is mis-linked or the user misspelled the address in the location bar, the "404" error.

500 to 599 represents various internal server error, the server may be down or the CGI scripts have software bugs. 500 errors may also mean that a request was denied for security reasons.

So what is out there besides Web pages?

FTP Sites:

Telnet sites:



Radio Stations:

Traffic Cameras:

Tell a robot to paint:

Coca-Cola Machines:

Useful Sites

Vast On-line Library:
On-line Medical Dictionary:
Dictionary Of Computer Terms:
How Stuff Works:

On-line Bible:
On-line Koran:
Maps and Driving Directions:
CIA World Factbook:
Shakespearean Insulter:


Internet - The global network of computers, servers, databases, routers and other machines. Includes the World Wide Web as well as non-viewable information and services.

World Wide Web - A collection publicly viewable pages and sites. Comprises a large part of the Internet.

Web Page - A single file written in HTML.

Web Site - A collection of web pages that are linked and, usually, exist on the same server.

URL - Universal Resource Locator. This is the in your location window, the address of a site.

Hyperlink - A button or link on a web page that opens another web page.

Intranet - A private network of viewable pages and sites, like our WEBS1.

Browser - A program that allows web pages to be viewed and accessed. Examples: Netscape and Internet Explorer.

ISP - Internet Service Provider, a company that sells access to the Internet. Examples: AOL, AT&T.

Protocol - A set of rules and instructions that computers use to pass information. HTTP, FTP, TELNET, HTTPS, TCP/IP and SMTP are all protocols.

HTML - Hyper-Text Markup Language, the code that most viewable web pages are written in.

HTTP - Hyper-Text Transfer Protocol, a set of instructions that tells your browser how to open documents accessed across the Internet. HTTPS is "secure" HTTP.

Cookie - A cookie is a small file that can contain your name, email address or other information. Web sites issue cookies to you when you visit them and log on. The next time you visit a site, it requests a copy of the cookie it gave to you earlier. This is how sites are "personalized." If you have ever visited a site that knows your name or email address, this is done with a cookie. You may refuse and delete cookies if you don't want them.

Virus - A program that is designed to hide itself on your computer and/or make copies of itself, and/or delete files from your system. The agency has a wide variety of virus protection in effect.

CGI - Common Gateway Interface. These are "active pages," forms, password windows, etc.

JavaScript - Active server pages, forms, clocks, and animation.

Java Applets - Interactive web programs.

FTP - File Transfer Protocol. A fast set of instructions for accessing files over the Internet. Unlike HTTP, which allows for viewing images and hyperlinks.

TELNET - A service for emulating a terminal connection to a remote server, similar to VT320.

SMTP - Simple Mail Transfer Protocol. Used for delivering and routing email.

Client - A browser requesting service from a remote host.

Server - A specially configured computer that has files and services that can be accessed across a network.

Host - A server or set of servers that have files or web sites accessible to clients.

Modem - For "Modulator-Demodulator" a device that turns the digital signal from your computer into analog signals for the telephone and vice versa.

Router - A device which receives and passes data along the Internet.

Backbone - A massive collection of servers and routers that make up the Internet's global service.

TCP/IP - Transmission Control Protocol/Internet Protocol. Protocol for most internet connections and network connections. For transporting all data not just web pages.

Creating Your Own Homepage

Use this script:



<TITLE>My Home Page</TITLE>



<H2> Welcome to my homepage</H2>

This is where the text of my homepage would go.

<A HREF=""> </A><BR>

Send me an email at:

<A HREF=""></A>



Copy the script exactly into Notepad, DO NOT USE MS WORD OR WORDPAD, and save it as index.html. Find the icon for this file and double click on it, it should open one of your browsers and display your page.


Editing the page:

Open your file in Notepad.

Replace "This is where the text of my homepage would go." With whatever message you would prefer.

Change "" and "" to a link of your own.

Change "" to your email address.

Save and click "Reload" on your browser.

Sites that offer free homepage space