A Firewall client is a computer with Firewall Client software installed and enabled. The Firewall client runs Winsock applications that use the Firewall service of Microsoft Internet Security and Acceleration (ISA) Server. When a Firewall client uses a Winsock application to request an object from a computer, the client checks its copy of the local address table (LAT) to see if the specified computer is in the LAT. If the computer is not in the LAT, then the request is sent to the ISA Server Firewall service. The Firewall service handles the request, forwarding it to the appropriate destination, as permitted. The Firewall Client software can send Windows user information, which is required for authentication purposes, to the ISA Server. For more information, see Firewall client components.
Setting up a Firewall client does not configure individual Winsock applications. Instead, it uses the same Winsock dynamic link library (.dll) that the other applications use. The Firewall client then intercepts the application calls and decides whether to route the request to the ISA Server computer. For more information, see Install Firewall Client software.
You can install Firewall Client software on client computers that run Windows ME, Windows 95, Windows 98, Windows NT 4.0, or Windows 2000. 16-bit Winsock applications are supported, but only on Windows 2000 and Windows NT 4.0.
Firewall clients are not supported in cache mode. For more information, see ISA Server modes.