Firewall Chaining as a Form of Network Routing
Firewall chaining is similar to Web Proxy chaining. In a Firewall chaining arrangement, the downstream ISA firewall is configured to be a Firewall client of the upstream ISA firewall. The advantages of the Firewall chaining configuration over the Web Proxy configuration is that Firewall chaining supports all TCP and UDP Winsock protocols, not just Web protocols (HTTP/HTTPS/FTP). In addition, Web Proxy chaining supports complex protocols that require secondary connections.
We have not been able to get Firewall chaining to work with the ISA firewall, so we will not cover the details of the configuration in this book. If this feature is repaired in a future service pack or feature pack, we will post this information as a detailed tutorial on www.isaserver.org.