A router connection is a high speed connection to the Internet using a router with an assigned IP address. For a router connection, your Small Business Server computer can be configured with either one or two network adapters.

In this configuration, both the server and the client computers use the router as the gateway to the Internet. This configuration is not recommended for the following reasons:

• Because ISA Server requires two network adapters to filter traffic from the Internet before it reaches your local network, it cannot be used as a firewall. With only one network adapter, client computers are not using ISA Server as a gateway; instead, they are connecting directly to the Internet through the router device.
• It is no longer possible to restrict Internet access to individual users. Since ISA Server is not monitoring outgoing Internet traffic, you will need to configure the router to deny access to particular Web sites or users.
• The Small Business Server Internet Connection Wizard cannot configure packet filtering. You will need to configure your router to allow the appropriate network traffic through to enable network services such as e-mail, Terminal Server, and so on.

In this configuration, the router is connected to the external adapter of the Small Business Server and the client computers are connected to the local network adapter of the Small Business Server. All of the client computers use the Small Business Server for their connectivity. The Small Business Server then forwards Internet-bound traffic through the router.

This is a recommended configuration because the client computers in the small business network are protected by ISA Server on the Small Business Server. ISA Server can also restrict Internet access by user account.

Important: If the router provides firewall capabilities, it is still necessary to configure the router correctly to allow the appropriate network traffic through.