Developed under the code-name "Catapult",[5] Microsoft Proxy Server v1.0 was first launched in January 1997,[6] 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,[7] Microsoft Proxy Server v1.0 only had basic functionality, and came in only one edition.

Microsoft Proxy Server v2.0 exited the extended support phase and reached end of life on 31 December 2004.

[10] ISA Server 2004 introduced multi-networking support[clarification needed], integrated virtual private networking configuration, extensible user and authentication models, application layer firewall support, Active Directory integration, SecureNAT[clarification needed], and improved reporting and management features.

[13]: 76 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.

[1] On 9 September 2012 Microsoft announced no further development will take place on Forefront Threat Management Gateway 2010 and the product will no longer be available for purchase as of 1 December 2012.