Securing Network Perimeters with ISA Server

  • Article

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

A perimeter network, also known as a screened subnet, is a network that is set up separately from an organization’s private network and the Internet. The perimeter network allows external users access to the specific servers located in the perimeter network, while preventing access to the internal network. In addition, an organization might allow very limited access from computers in the perimeter networks to computers in the internal network.

A perimeter network is commonly used for deploying the e-mail and Web servers. The perimeter network can be set up using either of the following configurations:

  • Back-to-back perimeter network configuration with two ISA Server–based computers on either side of the perimeter network.

  • Three-homed ISA Server–based computer with both the perimeter and internal network protected by the same computer.