LOCAL NETWORK PROBLEMS

Any time two or more computers and their related devices are under the same roof, they should probably connect to one another through a etwork. Networking allows users to share files and printers and to share access to the Internet through a common modem or broadband connection. Windows XP includes tools and wizards that make it relatively simple to set up a network, but a network is always more complicated than an isolated, stand-alone computer. Network problems don’t often interfere with the performance of your own computer, but they can be a source of serious aggravation when you need to open a file located someplace else on the net- work or use the network to print a document. Like any other type of computer troubleshooting, however, fixing a network is usually a matter of examining each element and returning the configuration back to the correct settings. The sources of most network problems are either configuration settings on one or more network devices, or firewalls and other Internet security software that block access to the other devices on the network. Of course, the complexity of a network increases with the number of devices connected to it, so troubleshooting a large network can be a long and tedious process. Big, sophisticated networks can have their own set of problems separate from those of the individual computers connected to them. Network trouble- shooting often requires a specialized set of tools and skills, but the general principles are relatively simple: check the connections and configuration of every device connected to the network, including all the computers, switches, gateways, modems, routers, and all of the interconnecting circuits.

In a corporate network, it’s entirely possible that some of the computers connected to it have been cranking along without any attention for many years. If your network develops a problem, the first step in solving it is often to identify all the devices connected to the network. During the Great Y2K Panic, when businesses were trying to update the software in all of their computers to prevent them from breaking down on January 1, 2000, some network managers discovered long-forgotten servers that had been operating for a decade or more. Those old faithful machines weren’t causing any problems, but they did add to the overall complexity of their networks. Even a small household network with just two or three computers con- nected to it can develop problems, often without any apparent warning. And unlike problems in a big corporate network, you can’t just hand them off to a network specialist. You’ll have to examine the network and identify the problems yourself. This article describes many of the most common network glitches, and it offers guidelines for dealing with them.

I Can’t See Other Computers on the LAN

You know there are other computers on your network; you can see them and touch them. But the My Network Places window doesn’t show that they exist at all. Here are some things to check:

Confirm that the computer you want to reach is turned on and the net- work cable is connected firmly at both ends.Confirm that power is connected to the network hub or switch. Right-click My Computer on the Windows desktop, choose properties from the pop-up menu, and select the Computer Name tab. Confirm that this computer and all the other computers on the network use the same Workgroup name. If the name is wrong, click the Change button next to the Rename This Computer option to open the Computer Name Changes dialog box. Change the name of the Workgroup to match the other computers on your network. If one or more computers appear to be offline but the others are accessi- ble, go to each of the “missing” computers and check its network config- uration settings: 1. Open the Local Area Connection Properties window (Start Control Panel Network Connections Local Area Connections Properties in the Windows XP Start menu or Start Settings Network

Connections Local Area Connections Properties in the Classic Start menu) and select the Client for Microsoft Networks item.

2. Confirm that the Client For Microsoft Networks item is active. If no check mark appears next to this item, click the name to turn it on.

3. Scroll down the list of items and confirm that the Microsoft TCP/IP Version 6 and Internet Protocol (TCP/IP) items are active. If you don’t see the Version 6 item, upgrade Windows XP to Service Pack 2 or later. Look for a firewall or other security program on the “missing” computer. Some security programs such as Norton Internet Security or the stand- alone Norton Firewall program default to blocking access from other computers on a local network. In either Norton program, follow these steps to configure the firewall to recognize other computers on your own network:

1. From the main Norton Internet Security screen, choose Personal Firewall, and click the Configure button.

2. In the configuration window, choose the Networking tab.

3. Click the Wizard button near the bottom of the window. The Net- work Wizard will step through a series of screens that will configure your system to recognize other computers on the same network.

Other firewall products may require a somewhat different or more complicated routine to permit access to other computers on the same network. The basic requirement is to specify either the individual numeric IP addresses assigned to other computers on your network or a range of addresses that includes all the computers on the network. Your firewall’s online help or its user manual should explain how to set these options. To find the numeric IP address assigned to each computer running Windows XP, open a Command Prompt window (Programs All Programs Accessories Command Prompt or Programs Accessories Command Prompt), and type ipconfig at the prompt.

The computer’s IP address will appear under the Ethernet adapter Local Area Connection heading. For computers running other operating systems, enter the same ipconfig com- mand at a command prompt. Repeat this process for each computer on the network. Three of the four sections of each IP address connected to the network should be the same; the numbers in the fourth section should all be within a range. For example, the IP addresses might all be between 192.168.1.50 and 192.168.1.100. That’s the range that you should instruct the firewall to accept. After you have identified the IP addresses and instructed the firewall to recognize them, go back to the first computer, and then open My Network Places. You should now see links to the other computers and other resources connected to your network.

File Sharing Doesn’t Work

Even though My Network Places tells you that a particular computer is con- nected to the network, you won’t be able to read or alter files stored on that computer unless file sharing is active. The My Network Places window shows an icon for each computer, but there appears to be nothing inside. Or maybe you can view some of the contents of a drive, but the particular file or folder you want is missing. The default setting for file sharing is to restrict access to the local com- puter. If you think about it, this is a useful feature of Windows networking rather than a flaw in the design. All of us have files that contain private information that we don’t want to share with anybody else; these might include personal financial data, competitive business information, or even old photos, love letters, and blackmail notes. If another person has unlimited access to all the files on your computer, there would be nothing to stop them from reading, changing, or deleting those files. Because of these risks, Windows doesn’t share your files unless you turn on file sharing. If you want to allow other people to read, change, or delete your files, you must take a couple of steps. Each computer controls access to its own files, so you can’t just turn on your own computer and automatically expect to see everything else on the network. You have to go to each computer and change that computer’s configuration first. To turn on file sharing follow these steps:

1. Run the Network Setup Wizard (Start Network Network Setup Wizard in the Windows XP Start menu or Start Settings Control Panel Network Connections Network Setup Wizard in the Classic Start menu), and step through each wizard screen.

2. When you reach the File And Printer Sharing screen, choose the Turn On File And Printer Sharing option.

3. Continue through the wizard to the end.

You’re not done yet. Turning on file sharing is only part of the process. You must also change the individual file sharing settings for each drive or folder:

1. From the Windows desktop, open My Computer. 2. Right-click the name of the drive or folder you want to share. 3. From the pop-up menu, choose Sharing And Security. The Properties window will appear.

The Sharing tab of the Properties window turns file sharing on and off.

4. To allow other users to view the contents of this drive or folder, turn on the Share This Folder option in the Network Sharing And Security box. If you allow sharing on a drive or a folder, all of the folders and files within that drive or folder will be shared as well. To permit other users to edit or delete the contents of files or folders within the drive or folder, turn on the Allow Network Users To Change My Files option.

When sharing is active for a folder or an entire drive, the icon for that object appears in My Computer and Windows Explorer with an open hand “serving” the icon. If other computers on the network can’t open a folder or another shared resource, even though file sharing is turned on and sharing is active, reset file sharing for that item:

1. Open My Computer from the Windows desktop.

2. Right-click the icon for the drive that you can’t open, or open the drive that contains the folder that won’t open.

3. Select Sharing And Security from the pop-up menu.

4. In the Properties window, remove the check mark from the Share This Folder option near the middle of the window.

5. Click the Apply button. Windows will change the setting and remove the serving hand from the icon.

6. Now click Share This Folder again to restore the check mark, and click the Apply button. After Windows has reconfigured the setting, the drive or folder should be visible to the network.

I Can’t Edit a File

If you can read, view, or play the contents of a file through your network, but the computer won’t allow you to edit or delete the file, check the Read-only status of the file and the folders in which it is stored. Also, check the Allow Network Users option in the Properties window described in the previous section (it’s directly under the Share This Folder option). When Read-only is active, Windows will not allow any user to make any changes to the contents.

This is not really a network problem, because it doesn’t matter if you’re trying to change a shared network file or one stored on your own computer: any read-only file or folder is protected. To check the Read-only status of a folder or file, open My Computer or the file share window that contains the file or folder, and right-click the icon. Choose the Properties item from the pop-up menu. The Read-only status appears near the bottom of the window.

At first blush, a local network for home computers might seem like a toy for geeks and gamers rather than something that the rest of us would ever need. But like the computer and the Internet, a home network can rapidly become an essential tool. Once you start using it, the network will become one of those things that you expect to find when you turn on a computer. When the network doesn’t work the way you expect it to work, you should know enough about troubleshooting to solve the most common problems and restore your connections.