Troubleshooting Q&A - December 23, 2003
Wired Networking, Step One – Choosing Your Connection
The first step in networking two or more computers is to determine how best to connect them. This week's Q&A looks at the pros and cons of networking via direct cable connections, hubs, switches, or routers.
By Ron Pacchiano
Q. I’m having a great deal of trouble getting my computers to network correctly and share an Internet connection. I have one desktop computer and one Laptop, both of which are running Windows XP Professional. My Internet access is being supplied by a Time Warner cable modem.
I tried connecting the computers together via an Ethernet cable, but they can’t seem to communicate with each other. I heard that it was possible to connect two PCs together in this fashion, but I can’t even get them to ping each other.
A friend of mine told me that I couldn’t network Windows XP PCs together like this and said that I should purchase a hub to solve my problem. I think this would work, but before I go out and buy one I just wanted to ask what you thought and find out if you have any suggestions for me. Thanks!
A. Well for starters, your friend is correct when he indicated that the hub would solve your problem. However, he was mistaken when he suggested that you couldn’t network two Windows XP PCs directly to each other.
I'm guessing the reason that you couldn’t ping between the two computers when you connected them via Ethernet cable is because you were not using a crossover cable. When you’re trying to network two similar devices, such as two PCs or two hubs or two switches, you need to use a crossover cable to connect them. The only exception to this would be if one of the products (like a hub or switch) has what's called an uplink port, or an auto-sensing port, on it. In that scenario, a standard Ethernet cable would work fine.
Crossover cables don’t look much different from normal (also known as straight-through) Ethernet cables, but they’re wired differently so that the transmit pin on one end of the cable matches the receive pin on the other. Incidentally, you can tell a crossover cable from a straight-through by holding the two connectors side by side with the tabs facing down. Look at the colors of the individual wires inside the connectors. If they don’t match, it’s not a straight-through.
That being said, you basically have two choices available to you for networking your computers. You can connect the two via a crossover cable, or you can use a hub and connect each computer to it with straight-through cables. If you think you might want to add additional systems to your network (or just for simplicity’s sake), stick with the hub.
If you decide that you want to stick with your original plan, connecting two PCs directly to each other is a relatively simple and straightforward process. For starters, you’ll need to purchase a crossover cable and connect it to the Ethernet port of each PC. Next, each PC’s Ethernet adaptor needs to be configured with a static IP address and a common Subnet mask. For our example, we’ll assign the first PC an IP address of 192.168.0.1 and the second PC an address of 192.168.0.2. Both machines should use the Subnet 255.255.255.0.
Also, you’ll want to make sure that both machines have been configured as members of the same workgroup. Any name will work for the workgroup name as long as it doesn’t exceed 15 characters (ex.WORKGROUP). All that’s left to do now is reboot the system. Upon reboot, go to a DOS prompt and try to Ping the other PC. To do this, just type PING and the IP address of the system you’re trying to reach (ex. C:\>PING 192.168.0.2). You should get 5 replies.
If for some reason your Ping returns a timeout message, you might have another problem. The most common issue has to do with Windows XP and the Internet Connection Firewall (ICF). The Windows XP Network Setup Wizard will sometimes enable ICF on your Ethernet adapter. ICF is designed to protect you from threats outside of your network by blocking unauthorized traffic from reaching your PC.
ICF is supposed to be used only on the interface that directly connects to your Internet connection; however, if ICF is being used on an interface that is being used to connect to another PC, it will block all the transmissions being sent to it. It will not even respond to pings. As a result, ICF must be disabled in order for this to work.
To disable ICF, simply right-click on “My Network Places” and select Properties. Right-click on your LAN connection and then select Properties again. Go to the Advanced tab and uncheck the box that reads “Protect my computer and network by limiting or preventing access to this computer from the Internet.” Click OK. Now try to ping the other PC again. It should work fine.
Now that your PCs can see each other, they need to be configured to share your Internet connection. This is done using Windows XP’s Internet Connection Sharing (ICS). Configuring ICS is a simple process, with detailed instructions available at http://support.microsoft.com/default.aspx?scid=kb;EN-US;306126. This article explains how to configure both the host and client sides of ICS.
My advice, forget about the hub and consider purchasing a Cable/DSL Router instead. There are a number of advantages in going this route. Most routers today are available with built-in switches that typically range from 4 to 8-ports, and they often include an integrated firewall. This integration allows you to get your PCs online quickly and saves you the headache involved in setting up Internet Connection Sharing (ICS) on the host and client PCs. Not to mention the fact that a switch performs much better then a hub.
Another benefit of using a router is that almost all routers give you the option of using DHCP for managing IP address assignments. This would simplify matters greatly because you wouldn’t need to bother with the network configuration we had to do when setting up the PCs with the crossover cable. And best of all, good routers that would meet your needs are available from D-Link, NETGEAR, and Linksys for only around $50-$100. Good Luck!
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