Internet,+intranet,+extranet,+virtual+private+network+(VPN)

The Internet carries an extensive range of information resources and services, such as the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support such as email.
 * The Internet ** - is a global system of interconnected computer networks that use the standard internet protocol suite to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies. Every computer that is connected to the Internet is considered a part of that network.

The internet has enabled us
 * To send email.
 * To view web sites.
 * To download files such as mp3 and images.
 * To chat with people live online.
 * To post messages on newsgroups and forums.
 * To play multiplayer games online.
 * To watch movies and tv programs.
 * To chat and view on webcams

And more...

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The extranet

An extranet is a computer network  that allows controlled access from the outside, for specific business or educational purposes. In a business-to-business  context, an extranet can be viewed as an extension of an organisation's <span style="color: windowtext; font-family: Arial,sans-serif; font-size: 10pt; text-decoration: none;">intranet <span style="font-family: Arial,sans-serif; font-size: 10pt;"> that is extended to users outside the organisation, usually partners, vendors, and suppliers, in isolation from all other Internet users. In contrast, <span style="color: windowtext; font-family: Arial,sans-serif; font-size: 10pt; text-decoration: none;">business-to-consumer <span style="font-family: Arial,sans-serif; font-size: 10pt;"> (B2C) models involve known servers of one or more companies, communicating with previously unknown consumer users. An extranet is similar to a <span style="color: windowtext; font-family: Arial,sans-serif; font-size: 10pt; text-decoration: none;">DMZ <span style="font-family: Arial,sans-serif; font-size: 10pt;"> in that it provides access to needed services for channel partners, without granting access to an organization's entire network. <span style="font-family: Arial,sans-serif; font-size: 10pt;">Virtual private network

<span style="background-color: white; font-family: Arial,sans-serif; font-size: 10pt;">The intranet is a computer network that uses Internet protocol technology to securely share any part if an organization’s information or networking operating system within that organization. It’s the connection of computer networks in a local area. The term used in contrast to the internet is that the intranet refers to a network within an organization. Like are school Jess.

<span style="font-family: Arial,sans-serif; font-size: 10pt;">A **virtual private network** (**VPN**) is a network that uses primarily public telecommunication infrastructure, such as the Internet, to provide remote offices or traveling users access to a central organizational network.

<span style="display: inline !important; font-family: inherit; text-decoration: inherit;"> It is basically a way to securely transmit private data over a public network.

<span style="background-color: white; font-family: Arial,sans-serif; font-size: 10pt;">VPNs typically require remote users of the network to be authenticated, and often secure data with encryption technologies to prevent disclosure of private information to unauthorized parties. <span style="background-color: white; font-family: Arial,sans-serif; font-size: 10pt;">VPNs may serve any network functionality that is found on any network, such as sharing of data and access to network resources, printers, databases, websites, etc. A VPN user typically experiences the central network in a manner that is identical to being connected directly to the central network. VPN technology via the public Internet has replaced the need to requisition and maintain expensive dedicated leased-line telecommunication circuits once typical in wide-area network installations.

VPNs typically mean remote access