Internet:Intranets, Extranets, Tunneling

Intranet
An intranet is a network of networks that is contained within a company or organisation. The main purpose of an intranet is to share company information and computing resources among employees. For example the latest product information can be downloaded to your workstation every morning, or you could complete staff training exercises on-line. An intranet can also be used to facilitate working in groups and for teleconferences. An intranet uses TCP/IP, HTTP, and other Internet protocols and in general looks like a private version of the Internet. It may consist of many interlinked local area networks. Typically, an intranet includes connections through one or more gateway computers to the outside Internet. Typically, users within the intranet to access the public Internet through firewall servers that have the ability to screen messages in both directions so that company security is maintained.

Extranet
Companies can send private messages through the public network, using the public network with special encryption/decryption and other security safeguards to connect one part of their intranet to another. When part of an intranet is made accessible to customers, partners, suppliers, or others outside the company, that part is called an extranet. It is also often possible for employees travelling away from their workplace or working from home to connect to their employers intranet, using via a login and password

Comparison of the Internet and Intranets
Table comparing Intranet and internet

Tunneling
Tunneling refers to using the Internet as part of a private secure network. The "tunnel" is the particular path that a given company message or file might travel through the Internet. This means that companies don’t need to use their own leased lines for wide-area communication but can securely use the public networks. A protocol called Point-to-Point Tunneling Protocol (PPTP) makes it possible to create a virtual private network using "tunnels" over the Internet. PPTP was sponsored by Microsoft and other companies.

The Onion Router AKA TOR
A smiler "Tunneling software" called TOR (Short for "The Onion Router" was developed in September 2002 by the US Navy with the main focus of online anonymity behind it but the project was later abandoned but picked up again in August 2004 by an online community in a goal for anonymous browsing.

In simple terms TOR works by filtering your browser request through multiple random TOR Clients(Typically users running the TOR software themselves) around world and then sends the servers message back a different path all while being heavily encrypted.

TOR Is a free open source software avaliable for download from & is supported on all Major PC platforms, Windows, OSX & Linux.