Microsoft Forefront Threat Management Gateway (TMG) is formerly known as ISA. TMG is an outbound and inbound access gateway. It is a comprehensive, secure Web gateway that helps protect employees from Web-based threats. It provides multiple layers of continuously updated protections, including URL filtering, antimalware inspection, and intrusion prevention. These technologies are integrated with core network protection features, to create a unified, easy-to-manage gateway that reduces the cost and complexity of Web security
Microsoft Forefront Unified Access Gateway (UAG) if formerly known as IAG. UAG is an inbound only access gateway. It provides browser-based remote access to published application via an SSL VPN portal. It delivers secure, anywhere access to messaging, collaboration, and other resources, increasing productivity while maintaining compliance with policy. UAG can also serve as a DirectAccess gateway, a deployment scenario for which the UAG provides incredible value.