Routing is something usually left to Cisco equipment or some other layer 3 device. Windows does include routing capabilites in Routing and Remote Access (RRAS) and TLA reader Jason Boche is back with a three part article on RRAS and how to configure it.

Understanding the fundamentals as well as the advanced configuration of the TCP/IP protocol is essential in most of today’s network infrastructures. Through the years we’ve seen many protocols. These protocols have risen and fallen in popularity based on trends, growth of network environments, and technical advances. Some, such as Microsoft’s NetBEUI, have disappeared from the list of protocols supported out of the box in Microsoft Windows products (although it can still be installed if you really need it).

Other protocols are seeing less use as time passes and will soon join the ranks with NetBEUI as a protocol of the past. One protocol that rose in popularity with the internet boom is TCP/IP. This is one protocol that is here to stay. Several years ago, Microsoft had an elective certification exam that was dedicated to the understanding of TCP/IP and its application in a heterogeneous Windows environment, meaning, master TCP/IP and its components with Windows, but also know how it loosely works with other systems in the enterprise such as Unix. Unfortunately, this exam was retired (it was one of my favorites), however, some of its legacy lives on in the current networking infrastructure exams offered by Microsoft. Furthermore, to underscore the importance of TCP/IP knowledge, Microsoft has made some of the network infrastructure exams a core requirement for the MCSA and MCSE certification tracks. Certification candidates and support staff alike in today’s world need to have a real good grasp of TCP/IP and many of its components consisting of TCP/IP related services and sub protocols.

In particular, Microsoft’s implementation TCP/IP focuses on DHCP, DNS, RRAS, as well as some legacy technologies like NetBIOS and WINS. Routing and Remote Access Service (RRAS) is the focus of this document, or at least, one part of RRAS which is Local Area Network routing with RRAS. I’ve always been fascinated with routing, more so the ability to multihome and route traffic with a Microsoft Windows Server operating system. Sure it doesn’t offer the complexity and capability of traditional network hardware such as Cisco, but not everyone needs that level of complexity. In some cases, not everyone can afford it. Part of being a good Engineer is providing the right solution for the job. Knowing when to implement a routed network with the expense of Cisco hardware can be as important as knowing when not to.

Maybe you’re the sole technician in an environment which calls for additional subnets but your budget can not afford Cisco hardware, training, consultants, or a support contract. Maybe you’re a consultant who’s introduced to a site using RRAS for a routing solution. These would be good reasons to opt for Microsoft’s RRAS. At the very least, you’re going to need to know TCP/IP, RRAS, and subnetting if you are an MCSA and/or MCSE exam candidate. Back in the day before x86 virtualization existed, setting up and practicing on a routed environment meant at a minimum 2 computers, 4+ network cards, CAT5 cabling, hubs or switches, a spare bedroom or ample room in the basement, and understanding housemates.

Now with virtualization products such as VMware Server and Microsoft Virtual PC, a practice lab can be set up on a single machine. No mess of cabling and equipment to trip over. Best of all, these virtualization products are FREE. For the procedures used in this writing, I’ve set up a lab that is represented by the following network diagram. There are three computers. Router1 and router2 are Windows Server 2003 Standard Edition machines each multihomed with two network cards. A third computer named timvpn is running Windows XP with one network card. This machine is used towards the end of the lab for ping and tracert diagnostic tests. The resulting configuration is three Ethernet subnets: 10.0.0.0/24, 10.0.1.0/24, and 10.0.2.0/24.

Below is an image showing the IP configuration on Router1. Note that when setting up a multihomed Windows router, the default gateway matches the IP address of the network card.

Here is a look at the IP configuration on router2. Again note the default gateway configuration for each network card.

Finally, here is a look at the IP configuration on timvpn. This is a Windows XP operating system with one network card. I’ve put it on the 10.0.0.0/24 subnet and assigned the appropriate default gateway that will be set up in a moment for that subnet.

On router1, open the Routing and Remote Access utility which can be found under the Administrative Tools program group. By default, RRAS is installed but not enabled or configured. The red symbol inside the circle just to the left of the server name indicates the RRAS service is not started on this machine. Using the RRAS utility, right click the server and choose Configure and Enable Routing and Remote Access.

The RRAS Wizard will start up and you can click Next to begin.

The following screen is where the various configurations of RRAS can be set up. This is where the initial choice is made on what kind of RRAS router this machine will be. For a Local Area Network router, choose Custom configuration and click Next.

Choose LAN routing and click Next.

Verify the summary configuration shows that LAN routing will be enabled and click Finish.

Immediately afterwards, you will be prompted to start the RRAS service now that it is configured; click Yes.

With RRAS installed, all that is left is the routing configuration.