Several elements determine how outbound requests for Internet resources are handled. These elements can be broken down roughly into two groups: Outbound Web protocol requests, and Outbound everything else.

You can configure the amount of server memory and other resources dedicated to servicing Web requests via the Performance page.

When you configure the Performance tuning slider bar to support more users per day, you dedicate more of the system resources to the ISA Server services.

ISA Server network configuration settings that influence outbound access controls include the following: routing SecureNAT and firewall client requests, routing Web Proxy Service requests, passing outbound PPTP requests from internal clients, the local address table (LAT), and the local domain table (LDT).

When firewall clients send their requests to the ISA server, the requests can be routed directly to the Internet via the primary connection on the ISA server, or you can configure the Firewall Service on the ISA server to forward the request to another ISA server.

The most common application of routing rules is to support Web proxy chaining. Web proxy chains can connect ISA servers located at different sites or LAN segments in a hierarchical fashion so that downstream ISA servers can take advantage of the cache contents of upstream ISA servers.

You can route Web proxy requests sent from clients to an ISA server to a Squid server and take advantage of the access controls...