Microsoft Forefront Threat Management Gateway networks are used to model your physical corporate networks. Forefront TMG constructs a number of predefined networks during installation. For more information see:
Internal and perimeter network properties
External network properties
Local Host network properties
VPN Clients and Quarantined Clients network properties
Using the Getting Started Wizard after Setup, you can configure a Forefront TMG network for each network adapter installed on the Forefront TMG computer. For more information, see Configuring initial deployment settings.
In addition to modeling your corporate environment, networks are also used to specify sources and destinations in firewall policy rules. For more information, see Overview of firewall policy. In addition to networks, Forefront TMG provides other types of network elements that can be used in rules. For more information, see Network objects.