Microsoft Forefront Threat Management Gateway (Forefront TMG), formerly known as Microsoft Internet Security and Acceleration Server (ISA Server), is a discontinued network router, firewall, antivirus program, VPN server and web cache from Microsoft Corporation. It ran on Windows Server and works by inspecting all network traffic that passes through it. Features Microsoft Forefront TMG offers a set of features which include: Routing and remote access features: Microsoft Forefront TMG can act as a router, an Internet gateway, a virtual private network (VPN) server, a network address translation (NAT) server and a proxy server. Security features: Microsoft Forefront TMG is a firewall which can inspect network traffic (including web content, secure web content and emails) and filter out malware, attempts to exploit security vulnerabilities and content that does not match a predefined security policy. In technical sense, Microsoft Forefront TMG offers application layer protection, stateful filtering, content filtering and anti-malware protection. Network performance features: Microsoft Forefront TMG can also improve network performance: It can compress web traffic to improve communication speed. It also offers web caching: It can cache frequently-accessed web content so that users can access them faster from the local network cache. Microsoft Forefront TMG 2010 can also cache data received through Background Intelligent Transfer Service, such as updates of software published on Microsoft Update website. History Microsoft Proxy Server The Microsoft Forefront Threat Management Gateway product line originated with Microsoft Proxy Server. Developed under the code-name "Catapult", Microsoft Proxy Server v1.0 was first launched in January 1997, and was designed to run on Windows NT 4.0. Microsoft Proxy Server v1.0 was a basic product designed to provide Internet Access for clients in a LAN Environment via TCP/IP. Support was also provided for IPX/SPX networks (primarily used in legacy Novell NetWare environments), through a WinSock translation/tunnelling client which allowed TCP/IP applications, such as web browsers, to operate transparently without any TCP/IP on the wire. Although well-integrated into Windows NT4, Microsoft Proxy Server v1.0 only had basic functionality, and came in only one edition. Extended support for Microsoft Proxy Server v1.0 ended on 31 March 2002. Microsoft Proxy Server v2.0 was launched in December 1997, and included better NT Account Integration, improved packet filtering support, and support for a wider range of network protocols. Microsoft Proxy Server v2.0 exited the extended support phase and reached end of life on 31 December 2004. ISA Server 2000 On 18 March 2001, Microsoft