This allows a local administrator to further restrict, but not override, the enterprise-level policy. While the ISA Server does boast intrusion detection as one of its features, this functionality is very limited, and is not enterprise quality. The optional firewall client is an interesting extension to the ISA Server. Designed for installation on the client machine of all firewall users, it allows policies based on transparent user authentication. The ISA Server provides a share containing the firewall client installation files.
Users simply browse to the share and run setup.exe to start the process.
The client setup modifies the browser proxy settings. Once installed, the firewall client will automatically detect the server and pass the user's credentials to the firewall, allowing rules to be enforced based on the user's identity. While the benefits to this type of operation are obvious, the firewall client has its limitations. For starters, the firewall client is only available for Windows-based platforms. Further, in order for the authentication to be seamless, the user must be logged in to an account that the ISA Server recognizes.