Small business Internet connectivity

There are a number of different methods to connect your small business network to the Internet.


Full-time Broadband Connection

A full-time broadband connection is a high speed connection to the Internet always available using a networking device such as a cable modem

or DSL modem. The full-time broadband connection requires two network adapters be installed in your Small Business Server computer. The first, an external network adapter, is used to connect your Small Business Server computer to the Internet. The second, a local network adapter, is used to connect your client computers to your Small Business Server computer. A full-time broadband connection also requires that ISA Server be installed to provide routing and NAT services.



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.

Using a Router With a Single Network Adapter

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.

If your router runs your DHCP server, it is also necessary to configure the appropriate DHCP options on your router. DHCP options are network configuration information used to automatically configure network settings for client computers. Refer to the DHCP section under “Network Services” for a list of the required DHCP scope options that should be configured on your DHCP server.

Using A Router With Two Network Adapters (Recommended)

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

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