An intranet is a computer network that uses Internet Protocol technology to securely share information within organizations. It is the connection of computer networks in a local area.
In contrast to internet an intranet is a network between organizations, and refers to a network within an organization. Sometimes, the term refers only to the organization's internal website, but may be a more extensive part of the organization's information technology infrastructure. It may host multiple private websites and constitute an important component and focal point of internal communication and collaboration. Any of the well known Internet protocols may be found in an intranet, such as HTTP (web services), SMTP (e-mail), and FTP (file transfer protocol). Internet technologies are often deployed to provide modern interfaces to legacy information systems hosting corporate data.
An intranet can be understood as a private analog of the Internet, or as a private extension of the Internet confined to an organization.
Source: wikipedia
