5. Extranet

An Extranet is one where people from outside the organisation can connect to the internal Intranet.

For example, external suppliers may have been set up to allow them to communicate via the company Intranet.

Remote business offices may be set up to use an intranet.

Employees on business travel may use an Extranet.

They are not connected directly to the LAN or WAN but instead are able to establish a connection with the correct equipment and authorisation.

Method 1: Mobile phone

A sales person on the road wants to connect to the company Intranet. They use the mobile phone network to contact the company's secure server.

Method 2: Virtual Private Network

With this method, connection to the company's secure server is made through the normal Internet. But now the secure server and the laptop will exchange secret keys which they use to encrypt all communication between the two. No one can eavesdrop on the data being exchanged. This is a 'virtual private network'.

Many teleworkers use a VPN to connect to their company Intranet.