One of the primary differences between Windows 2000 and Windows NT 4.0, outside of the Active Directory, is that Windows 2000 has a fully functional Routing and Remote Access Service. Unlike its predecessor, the Windows 2000 RRAS Service can act as a full service LAN and WAN router that you can put on your internal network, or at the edge of your network.
The Windows 2000 RRAS Service allows you to perform a number of functions that you could not in Windows NT 4.0. With the Windows 2000 RRAS, you configure input and output filters on each interface, configure support for RIP version 1, RIP version 2 and OSPF, and create demand-dial interfaces with demand-dial filters.
It's the latter feature that is the focus of this article. The Windows 2000 RRAS supports demand-dial routed connections. These demand-dial connections allow Windows 2000 routers to establish a link with a remote router when it receives a packet from the local network that is destined for a remote network that is reachable via the demand-dial interface. The Windows 2000 router will then dial up the connection to send the packet and will receive responses back from the demand-dial interface on the remote machine.
These demand-dial interfaces can save a company money, and can be security assets as well. Since these routed connections are not dedicated, you avoid the prohibitive costs of a dedicated WAN link. And, since the link is only available for the time that data is actively being transferred, potential intruders do not have unlimited access to the dial-up port.
If your company is considering a dial-up routing solution, you should check out these capabilities included with the Windows 2000 RRAS service. And, if you're studying for the Windows 2000 exam 70-216, you need to know RRAS like the back of your hand.