1. COMPUTER INTERNET, INTRANET & EXTRANET

2. INTERNET 1) It is a worldwide system which has the following characteristics: 2) Internet is a world-wide / global system of interconnected computer networks. 3) Internet uses the standard Internet Protocol (TCP/IP) 4) Every computer in internet is identified by a unique IP address. 5) IP Address is a unique set of numbers (such as 110.22.33.114) which identifies a computer’s location. 6) A special computer DNS (Domain Name Server) is used to give name to the IP Address so that user can locate a computer by a name. 7) For example, a DNS server will resolve a name http://www.tutorialspoint.com to a particular IP address to uniquely identify the computer on which this website is hosted. 8) Internet is accessible to every user all over the world.

3. INTRANET 1) Intranet is system in which multiple PCs are connected to each other. 2) PCs in intranet are not available to the world outside the intranet. 3) Usually each company or organization has their own Intranet network and members/employees of that company can access the computers in their intranet. 4) Each computer in Intranet is also identified by an IP Address which is unique among the computers in that Intranet.

4. SIMILARITIES IN INTERNET AND INTRANET 1) Intranet uses the internet protocols such as TCP/IP and FTP. 2) Intranet sites are accessible via web browser in similar way as websites in internet. But only members of Intranet network can access intranet hosted sites. 3) In Intranet, own instant messengers can be used as similar to yahoo messenger/ gtalk over the internet.

5. DIFFERENCES IN INTERNET AND INTRANET 1) Internet is general to PCs all over the world whereas Intranet is specific to few PCs. 2) Internet has wider access and provides a better access to websites to large population whereas Intranet is restricted. 3) Internet is not as safe as Intranet as Intranet can be safely privatized as per the need.

6. EXTRANET 1) An extranet is a private network that uses Internet technology and the public telecommunication system to securely share part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses. An extranet can be viewed as part of a company's intranet that is extended to users outside the company. It has also been described as a "state of mind" in which the Internet is perceived as a way to do business with other companies as well as to sell products to customers.intranet

7. 1) An extranet requires security and privacy. These can include firewall server management, the issuance and use of digital certificates or similar means of user authentication, encryption of messages, and the use of virtual private networks (VPNs) that tunnel through the public network.firewalldigital certificateencryptionVPNstunnel

8. COMPANIES CAN USE AN EXTRANET TO: 1) Exchange large volumes of data using Electronic Data Interchange (EDI)EDI 2) Share product catalogs exclusively with wholesalers or those "in the trade" 3) Collaborate with other companies on joint development efforts 4) Jointly develop and use training programs with other companies 5) Provide or access services provided by one company to a group of other companies, such as an online banking application managed by one company on behalf of affiliated banksaccess services 6) Share news of common interest exclusively with partner companies