What Is an Extranet?

An extranet is an intranet that can be accessed from the Internet. The Internet can be accessed by anyone, an intranet by people within an organization and an extranet by those who have authorization.

The Internet

If you are reading this article, you are already familiar with the Internet. The Internet resides on millions of computers throughout the world. The Internet is the sum total of this collective information.

An Intranet

An intranet is like an exclusive Internet. Unlike the Internet, where data from millions of public computers is available, an intranet resides on an organization's LAN (local area network). A group of private computers, isolated from the Internet, hosts HTML documents that can be read from a Web browser, giving the user an Internet-like experience. An intranet can only be accessed from within an organization.

An Extranet

When you have an intranet that can be accessed from outside of an organization, through the Internet, it is called an extranet. Extranets, like intranets, are somewhat private, with a limited few able to access it. In order to protect the private information on an extranet, users must provide authentication (passwords).

How Intranets Are Used

Intranets are used by companies and organizations as an internal electronic bulletin board of sorts. Individuals within an organization can share and exchange private information. For example, they might read and post events to community calendars, read internal memos or access the company directory.

How Extranets Are Used

Extranets are used much in the same way as intranets, except that they can be accessed remotely. An organization could use an extranet, for example, as a way to exchange large files between the organization and an outside contractor. All the outside contractor would need would be a password, so that they can access the extranet from the Internet.