Internet, Intranet, Extranet

Internet

in·ter·net  

/ˈintərˌnet/

An international computer network providing e-mail and information from computers in educational institutions, government agencies, and...The internet in simple terms is a network of the interlinked computer networking worldwide, which is accessible to the general public. These interconnected computers work by transmitting data through a special type of packet switching which is known as the IP or the internet protocol.

Internet is such a huge network of several different interlinked networks relating to the business, government, academic, and even smaller domestic networks, therefore internet is known as the network of all the other networks. These networks enable the internet to be used for various important functions which include the several means of communications like the file transfer, the online chat and even the sharing of the documents and web sites on the WWW, or the World Wide Web.

It is always mistaken said that the internet and the World Wide Web are both the same terms, or are synonymous. Actually there is a very significant difference between the two which has to be clear to understand both the terms. The internet and World Wide Web are both the networks yet; the internet is the network of the several different computers which are connected through the linkage of the accessories like the copper wires, the fiber optics and even the latest wireless connections. However, the World Wide Web consists of the interlinked collection of the information and documents which are taken as the resource by the general public. These are then linked by the website URLs and the hyperlinks. Therefore World Wide Web is one of the services offered by the whole complicated and huge network of the internet.

The use of IP in the Internet is the integral part of the network, as they provide the services of the internet, through different layers organization through the IP data packets. There are other protocols that are the sub-classes of the IP itself, like the TCP, and the HTTP

Intranet

in·tra·net  

/ˈintrəˌnet/

Noun

A local or restricted communications network, esp. a private network created using World Wide Web software.

 Contrary to popular belief, this is not simply a misspelling of "Internet." "Intra" means "internal" or "within," so an Intranet is an internal or private network that can only be accessed within the confines of a company, university, or organization. "Inter" means "between or among," hence the difference between the Internet and an Intranet.Up until the last few years, most corporations used local networks composed of expensive proprietary hardware and software for their internal communications. Now, using simple Internet technology, intranets have made internal communication much easier and less expensive. Intranets use a TCP/IP connection and support Web browsing, just like a typical Internet connection does. The difference is that Web sites served within the intranet can only be accessed by computers connected through the local network. Now that you know the difference between the Internet and an intranet, you can go around telling people on the street what you know and impress them.

Extranet

 ex·tra·net

An extranet is a controlled private network allowing customers, partners, vendors, suppliers and other businesses to gain information, typically about a specific company or educational institution, and do so without granting access to the organization's entire network. An extranet is often a private part of a website. It is restricted to select users through user IDs, passwords and other authentication mechanisms on a login page.

The difference between Internet, Intranet, Extranet

I/Net is used as an abbreviation of Internet and Intranet as Internets and Intranets share a lot of similar attributes such as IP addresses (see later).

Internet This is the world-wide network of computers accessible to anyone who knows their Internet Protocol (IP) address - the IP address is a unique set of numbers (such as 209.33.27.100) that defines the computer's location. Most will have accessed a computer using a name such as http://www.hcidata.com. Before this named computer can be accessed, the name needs to be resolved (translated) into an IP address. To do this your browser (for example Netscape or Internet Explorer) will access a Domain Name Server (DNS) computer to lookup the name and return an IP address - or issue an error message to indicate that the name was not found. Once your browser has the IP address it can access the remote computer. The actual server (the computer that serves up the web pages) does not reside behind a firewall - if it did, it would be an Extranet. It may implement security at a directory level so that access is via a username and password, but otherwise all the information is accessible.

Intranet This is a network that is not available to the world outside of the Intranet. If the Intranet network is connected to the Internet, the Intranet will reside behind a firewall and, if it allows access from the Internet, will be an Extranet. The firewall helps to control access between the Intranet and Internet to permit access to the Intranet only to people who are members of the same company or organisation. In its simplest form, an Intranet can be set up on a networked PC without any PC on the network having access via the Intranet network to the Internet. For example, consider an office with a few PCs and a few printers all networked together. The network would not be connected to the outside world. On one of the drives of one of the PCs there would be a directory of web pages that comprise the Intranet. Other PCs on the network could access this Intranet by pointing their browser (Netscape or Internet Explorer) to this directory - for example U:\inet\index.htm. From then onwards they would navigate around the Intranet in the same way as they would get around the Internet.

Extranet An Extranet is actually an Intranet that is partially accessible to authorised outsiders. The actual server (the computer that serves up the web pages) will reside behind a firewall. The firewall helps to control access between the Intranet and Internet permitting access to the Intranet only to people who are suitably authorised. The level of access can be set to different levels for individuals or groups of outside users. The access can be based on a username and password or an IP address (a unique set of numbers such as 209.33.27.100 that defines the computer that the user is on).