The Microsoft Forefront Threat Management Gateway product line originated with Microsoft Proxy Server.

Microsoft Proxy Server - replaced by Microsoft Forefront Threat Management Gateway (also known as ISA Server)

Microsoft Forefront Threat Management Gateway Medium Business Edition (Forefront TMG MBE) is the next version of ISA Server which is also included with Windows Essential Business Server.

Microsoft Forefront Threat Management Gateway (Forefront TMG), formerly known as Microsoft Internet Security and Acceleration Server (ISA Server), is a network router, firewall, antivirus program, VPN server and web cache from Microsoft Corporation.