This chapter deals with troubleshooting common networking issues. We present these issues from the perspective of a Tier 1 technician who might be unfamiliar with the networking capabilities of Microsoft Windows XP Professional and Windows XP Home Edition. Beginning with the basics (Is it plugged in?), we build to overviews of troubleshooting workgroup networks and domain networks. We then introduce name resolution and Internet Connection Sharing (ICS). We discuss different ways mobile devices communicate with desktop computers and each other, and we cover ways to enable a desktop computer to communicate with a mobile device.
In this section of the chapter we discuss physical connectivity. This can apply to issues as simple as a cable not being plugged in to a networking device being offline. We look at devices in the computer and teach students how to determine if the appropriate drivers are installed. Finally, we introduce Troubleshooters—the help tools provided with Windows XP to assist end users with finding and fixing problems with their systems.
During the discussion of this slide, try to work in the excellent point mentioned in the book about the possibility of broken cables. If wires within a cable jacket are broken, the only way you’ll know is by the link status lights on the devices to which the cable is connected. This can be on the network adapter itself or, if the network card does not have a status light, the hub or switch to which it is connected. If any question exists, try a spare length of cable. If the user has used the same computer for months with no problem, you might annoy him by making him crawl under his desk to check the connection. For this reason, you should consider other possible locations where connectivity might have been lost. Has anyone been adding connections in the wiring closet? Sometimes you (or an associate) will know of recent activity that will point to the cause. Often, however, a visit to the client site is necessary.
If all the cables are plugged in, a network device—either in the client computer, or elsewhere in the network—might have failed. Ask if other clients are experiencing the same problems. Try to determine the extent of the outage and compare these results with network diagrams to help find the possible location of the problem. Lead your students in a discussion of the campus network. If you are aware of any device failures, explain how the failed device was located. This can help make this a bit more “real” to your students.
If the computer experiencing problems is the only computer having such difficulties, it is time to begin looking for malfunctioning or disabled devices or improperly installed or configured drivers. This slide depicts a disabled modem and a network adapter configured with the wrong driver. Explain to your students the difference in the way these devices appear on this screen. Also explain that a dead or disconnected device will probably not be shown on the Device Manager screen at all.
You can quickly enable disabled devices by selecting the device and clicking the Enable icon on the toolbar, or right-clicking the device and selecting Enable. Explain to your students that it is often necessary to disable devices. For instance, you might disable a network device connected to a docking station at the office when you plan to use your notebook computer on the road.
This slide depicts updating a driver. Note how the device is found to actually be a different device than was initially installed. Windows XP has very strong device management capabilities. Often you can restore a seemingly broken device to operation simply by uninstalling it and restarting the computer. Windows XP performs hardware detection every time it boots, and will find and install appropriate drivers (if they exist) for any new device.
This slide depicts using the Modem Troubleshooter to troubleshoot an improperly connected modem. Suggest to your students that they might want to make use of the troubleshooters available in Windows XP until they gain more experience with locating the cause of trouble. A good way to find most of the available networking troubleshooters is to open Help and Support, select Networking And The Web, and choose Fixing Networking Or Web Problems.
In this section we discuss configuration of the network connection object in Windows XP. This might be a connection to the Internet, a connection to a workgroup network, or a connection to a Windows 2000 Server or Windows Server 2003 domain network. Emphasize that, unlike an Internet connection, the workgroup and domain connections go beyond configuring the physical connection to create a connection to the logical structures of a workgroup or a domain. This logical connection allows the computer to participate in file and printer sharing and other workgroup- or domain-based messaging functions.
Many of the topics related to this slide were discussed in Chapter 5, so use this opportunity to review the bullet points to determine if there are any questions among your students. Discuss dial-up settings, such as phone number, user name, password, idle time, redial on failure, and number of redial attempts. Determine that the IP address is valid, has the correct subnet mask, and is not being assigned by APIPA (all discussed later in this chapter). Check settings to allow communication with a DNS server for the purpose of name resolution. Check settings for e-mail and news, browser settings, and settings for instant messaging applications.
This slide depicts a small workgroup network. The following slide presents the Computer Name dialog box configured for connecting to this workgroup. Because access to resources is controlled by user name and password at the computer hosting the resource, it is not even necessary to have all computers use the same workgroup name. The workgroup exists solely to consolidate the view of the computers and their resources in My Network Places. Computers from the CONTOSGRA workgroup can view and access resources on other workgroups on the same LAN. All they need are the proper user names and passwords. These are maintained on each computer that shares resources with the workgroup.
You use the Computer Name tab of the System Properties dialog box to set computer name, set workgroup name, or join a domain. You might want to spend some time explaining that a workgroup is merely a collection of computers in My Network Places. A computer does not need to be a member of a particular workgroup to access resources on its member computers. Access is controlled locally at each computer that shares resources. Users authenticate when they attempt to access the shared resource.
When you have difficulty accessing resources on a computer in a workgroup, there are relatively few places to look for trouble. If the client computer cannot connect to any other members of the workgroup, you must look into physical connectivity and network adapter issues. If the network adapter is properly configured, you can then verify the IP address is valid for this network. This involves some knowledge of how IP addresses are configured and administered. Assuming the IP address is configured properly and you can actually see the other computers on the network, you might simply have an access control problem. Contact the administrator of the computer you are trying to access and obtain a valid user name and password.
Many common problem scenarios can be solved using the troubleshooters in Help and Support. This slide depicts a troubleshooter being used to solve a duplicate computer name issue in a workgroup. Feel free to spend some time discussing the available troubleshooters and some scenarios each might help solve.
This slide depicts a small domain network. The next slide presents the Computer Name Changes dialog box configured for connecting to this domain. In a domain-type network, each user has an account on the central domain controller. This allows administrators of computers that share resources to use the centralized list of domain user names to provide access to their resources. With a single list of authorized users, we prevent the administrative problems that can be created by administering several different lists.
This slide depicts the Computer Name Change dialog box while configuring a computer to join a domain. Because joining a domain requires a password with permission to join a computer to the domain, this task often falls to administrators. This slide is provided to familiarize students with the differences between the appearance of this dialog box for a workgroup connection and a domain connection.
If the client computer cannot see any other members of the domain or even log on to the domain, you must look into physical connectivity and network adapter issues. If the network adapter is properly configured, you can then verify the IP address is valid for this network. This involves some knowledge of how IP addresses are configured and administered. We cover this in more detail next. Assuming the IP address is configured properly and you can actually see the other computers on the network, you might simply have an access control problem. Contact the administrator of the domain and obtain a valid user name and password. Also contact the resource administrator to see if the user has been granted permission to access the resource. Be sure to remind your students that Windows XP Home Edition computers cannot join a domain.
This slide depicts the IP addresses most likely to be seen in daily use. Obviously much more goes into setting up IP networks, and that goes well beyond the scope of this course. The purpose of our discussion at this point is to familiarize your students with the appearance and usage of IP addresses.
One step that you can take to attempt to restore connectivity is to use the Repair tool for network connections. Especially in domain-type networks where use of dynamic address allocation and advanced name resolution are more likely to be in effect, Repair helps you eliminate many manual checks and tests. The Repair tool renews the IP address using DHCP (if configured). It flushes all name resolution caches (NetBIOS and DNS). It also reregisters the computer name with the DNS server and flushes the Address Resolution Protocol (ARP) cache. Instead of performing these tasks manually, using Repair enables you to perform them with a single step, which saves you valuable time and might resolve the problem.
Details of how DHCP leases addresses are beyond the scope of this course. Likewise, technical explanations of APIPA will probably give the students more than they need right now. Instead, discuss in broad terms the purpose of each, and how APIPA can be used on smaller networks as an alternative to a DHCP server. Explain how to determine if an address has been assigned by APIPA (an address in the 169.254.0.0 network) and how to resolve these situations (which is most often to contact the administrator of the DHCP server to get it back online). You might also want to offer a teaser for Internet Connection Sharing (ICS), indicating that it also has the ability to dynamically allocate addresses to provide Internet connectivity to small networks. We expand on ICS at the end of this chapter.
Isolating name resolution problems need not be difficult. Any time you can connect to a host by IP address but not by name, there is a problem with resolving the name of that host. The tools listed on the slide are all useful in testing TCP/IP connectivity, but most important among them is Ping. To test DNS name resolution, ping a known host, first by name, then by IP address. If both succeed DNS, name resolution is operational. Likewise, to test NetBIOS name resolution, ping a known host, first by NetBIOS name, then by IP address. Once again, success proves NetBIOS name resolution is operational. More difficult name resolution scenarios do exist, such as failures of remote WINS servers, and invalid NetBIOS scope types, but these are beyond the scope of this course. Any failure beyond the simple tests provided would be passed to an administrator or engineer for resolution.
This slide provides bullets for a discussion of DNS functionality. Describe this service as series of servers configured to resolve host names in fully qualified domain name (FQDN) format to IP addresses. Spend some time describing the Internet name hierarchy from top-level domains, down through second-level domains, sometimes to subdomains, to host name. Map out an FQDN such as www.support.microsoft.com.
This slide presents the WINS server function. Describe NetBIOS naming, and show the students what a NetBIOS name looks like. Describe the role of a WINS server to provide name resolution services for networks that still rely on NetBIOS names for communications.
A Windows XP computer has the ability to share its connection to the Internet with other computers, which is a great feature for small offices. Be sure to explain what happens when you enable ICS: The IP address of the computer’s internal network adapter is automatically set to 192.168.0.1. The ICS computer is configured to allocate addresses from the 192.168.0.0 network to other computers on the network, which means that all other computers must be configured to obtain an address automatically. This can conflict with DHCP, so avoid using ICS on a network with a DHCP server. Each client computer will be configured with the ICS computer’s address as the default gateway.
You can enable ICS either directly in the Advanced tab of the Internet Connections Properties dialog box, or through the services of the Network Setup Wizard. When there are problems with an ICS installation, it is often easier to disable and enable it than to spend time rooting out the cause.
It is necessary at this point to introduce the different types of devices your students might see on the job. These typically range from inexpensive pocket organizers to the latest tablet PC technology. We are concerned in the chapter mainly with connectivity, not with supporting the actual devices.
Pocket organizers work well when one needs to keep track of only names and addresses. Some support connectivity to desktop computers, but most do not without an adapter kit at an extra cost.
PDAs, such as Pocket PCs or Palm devices, offer more powerful applications and functionality than pocket organizers. Most include the ability to author and read e-mail, and some even include Internet connectivity.
Smart displays allow users to undock their monitor and carry it into another room. Once there, they have the option of using it as a notepad, using a stylus and handwriting recognition to enter data. Alternatively, they can dock it into a remote cradle and use a keyboard and mouse to control the computer in the other room.
Tablet PCs offer the ability to run pen-based applications such as note taking or forms entry. They might be convertible units that support operation as a tablet or a notebook computer. Tablet PCs typically run Microsoft Windows XP Tablet Edition.
A number of technologies exist to connect handheld devices with desktop computers. To allow effective communications, you must find a technology both units support. In some cases, this means choosing a slower technology such as serial communications. Many devices now support more than one method of connectivity. It is important in these cases to choose the fastest common connectivity method.
Although serial connectivity might be slower and require some manual configuration, it is the most widely supported method of connectivity. Most handheld devices have adapters available for this connection method. When you are configuring serial communications for handheld devices, choose the same settings for both devices to allow them to communicate.
Parallel ports are sometimes used to connect two desktop computers together to share files. This use, however, is declining as Ethernet technology becomes less expensive.
USB supports higher speed communications between handheld devices and their hosts. Also, USB supports the greatest number of peripherals. In addition to handheld devices, USB supports scanners, printers, digital cameras, portable storage devices, and more.
Not many handheld devices support the FireWire specification. It is used more often to connect computers with high-end devices such as digital cameras, video cameras, and printers.
Used primarily to share contact data between PDAs, IrDA is also used to print wirelessly from notebook computers and PDAs. IrDA connections must have a line of sight between hosts. IrDA supports a limited range. Strong sources of infrared light will disrupt IrDA communications.
Wireless Ethernet is being used more often to connect devices to networks and each other. It is becoming available for media applications as well. Handheld devices supporting this connection method typically use it to access Internet resources well.
Each device that connects to and shares data with a desktop computer will have an application that manages that process. In the case of Pocket PCs, that application is Microsoft ActiveSync. This slide shows the look and configuration of ActiveSync. Be sure to point out the different connectivity methods available for devices to connect with this computer.
Most communications troubleshooting involves troubleshooting the method of connectivity. This might be as simple as checking the cables and whether they are plugged in. If connections are good, there might be a configuration or device driver problem with the port. BIOS settings might also have disabled the port. If this is the case, the port does not even appear in Device Manager.
Verify connectivity using link status lights when possible to avoid missing broken cables. Check Device Manager for missing or improperly configured devices.
Review common troubleshooting tools again. Describe the steps to ping out from a system to locate the cause of problems. Review how to test name resolution. Remind students that ICS usurps the role of a DHCP server and will disrupt a network that relies on one.
Review the connectivity methods and present some scenarios where lack of connectivity might be due to improper configuration.
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