The Internet is the ultimate network. It is a huge collection of computer networks connecting millions of computers, people, software programs, databases, and files. The parts and players are spread around world and interact continuously. Any two connected computers can be considered a network. Any two connected networks become an internet (small " i "). Technological advancements over the last few years have enabled almost all computers to be networked together, giving birth to today's Internet (capital " I "). Small Van Insurance A Commercial vehicle insurance guide AA or RAC A guide to car breakdown cover and breakdown insurance.

The Internet was created in 1973 by the U. S. Defense Advanced Research Projects Agency (DARPA) to ensure that their communications systems would continue to work in the event of nuclear war. For most of its existence the Internet was primarily a research and academic network. More recently, commercial enterprises and a vast number of consumers have come to recognize the Internet's potential. Today people and businesses around the world can use the Internet to retrieve information, communicate and conduct business globally, and access a vast array of services and resources on-line.

No particular group or organization owns or controls the Internet. It is actually a worldwide network that links in excess of 100,000 other networks. Volunteer groups of individuals do set some standards for Internet technologies, but there is no central body that governs the structure.

Millions of people use the Internet for its electronic mail capabilities. Electronic mail however, is only a small part of what the Internet offers. Users can join any of the thousands of Internet discussion groups, search for specific information in vast libraries, or transfer a variety of files to their computer. They can also explore the World Wide Web, the Internet's multimedia service. Over just the last few years Internet-based resources and services have grown exponentially. Based on current projections this rapid growth will continue into the next decade as more businesses and consumers make the decision to move onto the Internet.

When you send a message over the Internet, it is broken into tiny pieces, called packets, which travel over many different routes between your computer and the recipient's computer. The communications protocol used to route the packets across the Internet is TCP/IP (Transmission Control Protocol/Internet Protocol). Use of this standard protocol enables computers using different operating systems to communicate with each other. DOS-based PCs, PCs using the Microsoft Windows©, Windows 95, or Windows NT operating system, Macintosh© computers, and UNIX©-based systems all use TCP/IP to connect to the Internet.

One of the biggest obstacles for realizing the full potential of the Internet has been the issue of security.There are three basic levels of on-line activity requiring transit security: General Communications, Business Communications, and Financial Transactions.

The simplest application is general communications such as private e-mail or limited access to data on a Web page. An example might be a situation where both sender and receiver (or client and server) know what data is being sent back and forth, but they would prefer not to share this information with others. In situations such as this a password system is employed to ensure that the access is allowable, or "authentic."

In business communications, authentication and message integrity, as well as privacy can be critically important.
Financial transactions require additional security measures. Obviously, authentication is a big issue for credit card users. From the merchants' viewpoint, it is essential that customers cannot deny valid transactions: "non-repudiation" is the inability to deny having made an action , essentially the equivalent of a signature. Merchants need to be sure that customers will pay for merchandise before sending goods. Furthermore, financial data must be partitioned on a need-to-know basis. Many financial transactions, such as using bank cards, involve more than two parties, the merchant and the card holder. Each party needs some data, but at least one party shouldn't have access to all data.

Once you connect to the Internet, you interact with other computers using a client/server model. The resources of the Internet , information and services, are provided through host computers, known as servers. The server is the computer system that contains information such as electronic mail, database information, or text files. As a customer, or "client," you access those resources via client programs (applications) which use TCP/IP to deliver the information to your screen in the appropriate format for your computer.

Every resource on the Internet has its own location identifier or Uniform Resource Locator (URL), an Internet address. This helps users identify the source of any information on the Internet. When you know the URL, you can key it in for immediate access to that resource without browsing through directories or using keyword searches.

The first part of the URL indicates the access method or protocol used by that server. For instance, all Web sites would have a URL that begins with "http", since that is the protocol for accessing the Web.

The second part of the URL is the computer's domain name, which is described below. For example, http://www.netcar.co.uk is the locator for the Web page for the Netcar sales on-line service. The www indicates this is a Web home page, netcar is the name selected for this site, the .co.uk indicates this is in the U.K. company domain of the Internet. In addition, every computer, client or server, on the Internet has a unique IP (Internet Protocol) address to distinguish it from other computers on the Internet. The IP address is four sets of digits separated by dots. Since this string of numbers would be hard to remember and fraught with potential keying errors, the Domain Name System (DNS) was created so people wouldn't have to remember several confusing numbers. Domain names enable short, alphabetical nicknames to be assigned to IP addresses to describe where a computer is located. For the most part, domain names indicate who or what is located at this site and the type of organization that owns or supports the site. In the URL example above, www.netcar.co.uk is the domain name for the Netcar Web site.

Some domain types you might see are:
.com Commercial Organizations
.edu Educational Institutions
.gov Government Organizations (except the military)
.mil Military Organizations
.net Network Service Providers
.org Organizations other than those above

Here are some examples of international domain designations:
.au Australia
.fr France
.uk United Kingdom
.us United States
.es Spain

The InterNIC (Internet Network Information Center) exists to issue IP addresses and domain names so that duplicate names or addresses do not proliferate. New users, or existing users requiring additional Internet addresses, need to apply to the InterNIC for these resources.

A Browser is a client program (application) that is used to search through information provided by a specific type of server. A browser helps you view and navigate through information on the Internet. Today's most popular browsers, including Mosaic©, Netscape Navigator, and the Microsoft Internet Explorer offer a graphical interface to the World Wide Web.

Electronic mail, the sending and receiving of electronic messages, is currently the most popular use of the Internet. E-mail is also used on most commercial on-line services, and for many people, is the primary reason for getting onto the Internet or an on-line service.

To send e-mail, you must know the recipient's e-mail address. These addresses are composed of the user's identification, followed by the "@" sign, followed by the location of the recipient's computer. For example, the e-mail address for APEC Computer Services is harvey@apec.co.uk. The last three letters indicate this location is a UK company domain on the Internet. When you access the Internet through a local service provider or one of the large commercial on-line services, you can exchange e-mail without incurring the long-distance charges of a telephone call. Depending on the service package you have selected, e-mail can be an economical alternative for some telephone usage. E-mail has the added advantage of allowing you to access messages and at your convenience. You can also send an identical message to any number of people at the same time.

NNTP (Network News Transfer Protocol) is an Internet standard protocol defined for distribution, inquiry, retrieval and posting of news articles. Network News (USENET) is a popular usage of NNTP. It offers bulletin boards, chat rooms, and netnews, which is a massive system with over 5,000 ongoing conferences, called newsgroups, conducted around the clock, 365 days a year. To access these newsgroups, you download a special program from the Internet that allows you to participate in any newsgroup you wish. Most commercial browsers have this capability built in. You then "subscribe" to those newsgroups that interest you and communicate through a message system similar to e-mail.

You may simply view an ongoing dialog without participating (this is called lurking) and is encouraged for newcomers. To enter the conversation, you "post an article" in the newsgroup and you become part of the forum. As with e-mail, Netnews is usually informal communication between individuals (albeit thousands of individuals!), with little distillation of content. However, some newsgroups are managed by a monitor who may elect not to post responses that are deemed inappropriate for that forum. Usenet operates at a very high speed, with postings appearing quickly and constantly. Group administrators set the length of time that messages remain posted before being deleted from the system. Most do not keep postings longer than a week.

Discussion groups and chat rooms can be excellent sources of information and assistance on technical issues, hobbies, travel, etc. They can also be sources of lively political debate and an opportunity to meet people with shared interests.

Another widely used tool of the Internet is Gopher, a menu-based program that enables you to browse for information without having to know where the material is specifically located. It lets you search lists of resources, and then helps send the material to you. Gopher is probably the most comprehensive of all browser systems and is integrated to allow you access to other programs including FTP and Telnet.

When you use Gopher, you cross the Internet by moving deeper and deeper into the menus. Using Gopher, you can access library catalogs, files, and other databases. For example, if you are looking for a poem written by your favorite poet, you might look first under authors & books, and then under poetry.

Veronica and Jughead are related programs that assist your search of Gopherspace (the term for the collective assortment of Internet sites that run Gopher software). Veronica helps you search gopher systems for documents; Jughead searches directory titles only.

Sometimes browsing for information is not enough, you may want to obtain copies of software programs or data files for your own use and manipulation. FTP is a method of transferring files from one computer to another over phone lines. You can transfer many different types of files to your computer. For example, you may want the latest upgrade for a particular software product, or you might find your favorite movie star's photograph. This feature allows access to information more quickly than sending disks and hard copy materials through regular, or even express, mail.

There are probably millions of files available via FTP on the Internet. The search tool Archie, a client program, helps you find files stored on FTP sites using keywords that appear in the file names. You enter likely keywords and Archie searches its database for matches. Archie then sends you a list with full file names and the address information you need to retrieve the file via FTP.

Another way to access information from servers is to actually log on to a remote computer and use it. Telnet provides that capability. When you connect, your computer acts as if your keyboard is attached to the remote computer. You can use the same services as a local user.

This means that you can run programs on a computer on the other side of the world, just as if you were sitting in front of it.

You might use Telnet to look at the electronic card catalog from the Library of Congress or the British Library in London. You might also use Telnet to browse through government databases. One potential downside to Telnet is that you must know how to use the computer you have logged on to. The remote computer must also grant you access. A number of organizations have written special programs into their systems so that Internet users can have ready-access to information.

The World Wide Web is the multimedia part of the Internet. It is currently the fastest growing part of the network. WWW content displays as a page and, unlike other Internet sites, text is formatted in various fonts, styles, colors and sizes. Pages may also contain pictures, sounds, and movies.

Hypertext Transfer Protocol (HTTP) is the standard language that allows Web clients and servers to communicate. Sometimes WWW servers are called HTTP servers and, as explained earlier, http is the path name for Web sites.

Web sites use hypertext to display links to other pages. By clicking on these links, you can go directly to other pages or sites on the Web. You can also access other key tools of the Internet, such as FTP and Gopher, to help you explore and access Web resources. Browsers are available to help you view and navigate through Web pages easily.

A variety of companies and organizations such as APEC Computer Services establish Web sites by providing Web pages. Some organizations may want to sell their products, while others may simply want to tell you about themselves. Individuals can also develop their own personal Web pages. The initial screen you see when you access a Web site is commonly referred to as a home page.

There are currently two basic ways to physically connect to the Internet. The first, and most widely used method is through a modem which connects your computer to a normal analog telephone line, which in turn connects to a modem at the host computer. This is called a dial-up account, because your computer goes through a process similar to dialing a phone number to gain access. The second method for connecting to the Internet does not involve modems and is referred to as an ISDN connection.

There are several variations to the dial-up account which provide different capabilities, depending on the protocols used. All of these connections require the Internet Protocol, and are therefore called IP accounts. The three types of IP accounts are: PPP, which stands for Point-to-Point Protocol; SLIP, which stands for Serial Line Internet Protocol; and CSLIP, which is a compressed version of SLIP. PPP is the emerging connection of choice because it is faster and more reliable. But PPP is also more complex, so many computer platforms still only have built-in support for SLIP. Supplemental programs are being developed to enable most platforms to support PPP accounts.

Integrated Services Digital Network (ISDN) is a telecommunications service which connects networks through digital lines using a terminal adapter. ISDN provides a faster connection and can be more economical. In the future, ISDN boards designed to support ISDN connections through the PC will be commonplace.
Theoretically, both methods can connect single-user accounts or multiple-user accounts to the Internet. Dial-up accounts are probably most affordable for single-users, but ISDN provides a more economical solution for Local Area Networks (LAN), which connect multiple users at a specific location to the Internet.

With the advent of Internet protocols, modems, and Web browsers, virtually anyone can gain access to the Internet. But first they will need something comparable to a new kind of utility company, they will need an Internet Access Provider (IAP). This can be a small local operation or one of the large commercial on-line services, or something in between. Historically, the commercial on-line services have not been considered IAPs and their Internet-access tools have been less than optimal.

Organizations which want to link several computers together to share files and exchange e-mail may want to set up a LAN with access to the Internet. This is an economical alternative to providing each individual with a modem and SLIP or PPP dial-up capability. Workstations on a LAN are normally located in close proximity to each other, usually within the same building. A LAN connection will allow multiple users to access the Internet under a single domain name. LAN connections to the Internet are typically done via ISDN or with a leased telephone line. User IDs are assigned to individuals for logon purposes and for directing e-mail.

One potential drawback to a LAN connection is that other Internet users could gain access to files and data residing on the LAN. This can be prevented by establishing a security system such as a "firewall". A firewall usually consists of a single machine that is connected to the Internet and all Internet traffic on the LAN must pass through that machine. This machine is set up to prevent or restrict users on the Internet from accessing data on the attached LAN. It can also be set up to restrict access from the LAN to the Internet.

In addition to accessing Internet resources through either dial-up or LAN accounts, you may also wish to establish your own server presence. Depending on the type of service you want to provide, you may choose to create a server for E-mail, FTP, Gopher, World Wide Web or a combination of these. Server services are available to help you design, establish, and maintain a server presence on the Internet.

The World Wide Web has become the tool of choice for establishing an Internet presence. By establishing a Web Site, a company or an individual can advertise services, provide detailed product information, and even conduct transactions, promote themselves in seeking job opportunities, or simply tell the world they exist.

Establishing a server for any Internet tool requires using specific protocols and programs. All Web clients and servers must be able to speak HyperText Transmission Protocol (HTTP) in order to send and receive hypermedia documents. Because the HTTP protocol is the foundation for most Web transactions, Web servers are usually called HTTP servers.

Currently most Web servers run on UNIX servers. However, this domination of the Internet by UNIX servers is likely to change due to the rapid growth in Microsoft Windows NT Server installations and due to the introduction of Microsoft Windows 95.

A Web page is created by formatting text with styles and links using HyperText Markup Language (HTML), the standard format for the World Wide Web. HTML commands (referred to as tags) are added to the text file, or source document. The source document can be created using a word processing program, such as Microsoft Word.

For many people, the best way to access the Internet is to use a commercial on-line service, such as U-Net,The Microsoft Network, CompuServe©, America OnLine©, or Prodigy. Most of these services combine limited Internet access with unique fee-based services available only through their commercial connection. For some users, there are advantages to using these service providers over direct Internet connections. One advantage may be the wide assortment of commercial-quality information, which the on-line service purchases from commercial servers and then sells to their users. In many locations, commercial on-line services provide access with a local phone number, precluding long distance charges for connection to the Internet. This could be a key advantage in locations that do not have local Internet service providers.

All commercial on-line services allow you to send and receive e-mail via the Internet. Many are starting to add the other main Internet services such as WWW, Usenet news, FTP, Telnet, and Gopher. As commercial services evolve and continue to compete for market share, they will differentiate themselves mainly by cost, specialized services, reliability, and unique restrictions such as storage space, time limitations and parental guidance warnings.