If you have a small business you might want your LAN clients to access the Internet. By installing Windows NT with a network adapter card connected to your LAN, and another network card for your Internet connection, you can create two-way communication with the Internet by configuring Windows NT as a simple router.
Figure 20.3 Small LAN Client Access to the Internet Using Windows NT
Windows NT is suited as a TCP/IP router only in small, single subnet networks because Windows NT does not process the RIP requests that automatically maintain a TCP/IP router table. If you have a larger network, with more that one subnet, you probably need the performance of a dedicated router (and likely have routers in your network already).
Figure 20.4 Large LAN Client Access to the Internet Using Third-party Router