ISA下的三种Clients

Firewall Clients

ISA Firewall clients are computers that have Firewall client software installed. Requests from Firewall clients are directed to the Firewall Service on the ISA Server computer to determine if access is allowed. Subsequently, requests may be filtered by application filters and other add-on filters. If the Firewall client requests an HTTP object, then the HTTP Filter redirects the request to the Web Proxy service. The Web Proxy service may also cache the requested object or serve the object from the ISA Server cache.

The Firewall service supports Windows Sockets version 1.1 applications. Before a Windows Sockets application can gain access to the Internet through ISA Server, the server must be configured to permit user access for the required protocol on the required service ports.

You can install ISA Firewall Client software on client computers running Microsoft Windows 95, Microsoft Windows 98, Microsoft Windows NT® 4.0, or Windows 2000. When you set up ISA Server, you configure the array to which Firewall clients should connect when sending requests to the Internet. You can specify the array by DNS name or by IP address.

SecureNAT Clients

As noted earlier, SecureNAT clients are computers that do not have the Firewall Client software installed. Requests from SecureNAT clients are directed to the SecureNAT layer. The client request is inspected by the Firewall Service to determine if access is allowed. If it is, the request is then handled by the SecureNAT engine, which substitutes a global IP address that is valid on the Internet for the internal IP address of the SecureNAT client. Finally, application filters and other add-on filters may filter the request. If the SecureNAT client requests an HTTP object, then the HTTP filter redirects the request to the Web Proxy service. The Web Proxy service may also cache the requested object or serve the object from the ISA Server cache.

Web Proxy Clients

Web Proxy clients are any CERN-compatible browser application. Requests from Web Proxy clients are directed to the Web Proxy Service on the ISA Server computer to determine if access is allowed. The Web Proxy service may also cache the requested object or serve the object from the ISA Server cache.

You can configure the Web browser client after installing the ISA Server client software. Each Web browser is configured through its own user interface—typically, by menu items such as Options, Preferences, or Settings.

When you install ISA Firewall Client software, the Web browser settings on the firewall client desktop can be configured automatically. Subsequently, you can reconfigure the Web browser clients.