Firewalls
Virtual Private Networks

In recent years it has been cheaper to connect 2 LANs, privately owned by a company, via the Internet - a public network, rather than via a private line. This practice does make the connection between the 2 LANs insecure, as now hackers connected to the Internet can access the machines on them. A secure connection using Firewalls and secure Internet protocols can be made between them. ¹ This connection is called a Virtual Private Network (VPN) and means that data can be sent between the two LANs without any worry of it being seen or copied by unscrupulous hackers.

VPNs can be implemented as part of the gateway router(firewall) to a private network or maybe a server running, for example, Windows 2000. The diagram shows a VPN tunnel created through the Internet using either a router or a server. If the VPN is created on a server it is a good idea to place a Firewall router between it and the Internet.

[1] Protocols - The rules that are used to send the data across the network cabling and equipment.