An organization uses the Internet to communicate public information about itself to members of the organization and to others outside the organization. And like we already discussed, Intranets and Extranets are private versions of the Internet.

An organization uses an intranet to share information between the members of the organization. Organizations use extranets to exchange information with and provide services to their business partners (customers, suppliers, etc.)

An extranet requires security and privacy that require 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 (VPN) that tunnel through the public network.