Forefront TMG includes four different network templates, that can fit in your existing network topology. It is important to choose the most appropriate for your organization option. After installing TMG, the Getting Started Wizard will appear, where you need to make initial configuration to your TMG. The first menu of the Getting Started Wizard is Configure Network Setting, where you need to make your choice about what network template to use. See bellow the available options.
Edge Firewall - In this topology, Forefront TMG is located at the network edge, where it serves as the organization’s edge firewall, and is connected to two networks: the internal network and the external network (usually the Internet).
3-Leg Perimeter - This topology implements a perimeter (DMZ) network. Forefront TMG is connected to at least three physical networks: the internal network, one or more perimeter networks and the external network.
Back/Front Firewall - In this topology, Forefront TMG is located at the network’s back-end. Use this topology when another network element, such as a perimeter network or an edge security device, is located between Forefront TMG and the external network. Forefront TMG is connected to the internal network and to the network element in front of it.
Single Network Adapter - This topology enables limited Forefront TMG functionality. In this topology, Forefront TMG is connected to one network only, either the internal network or a perimeter network. Typically, you would use this configuration when Forefront TMG is located in the internal corporate network or in a perimeter network, and another firewall is located at the edge, protecting corporate resources from the Internet.