CHAPTER 50. Troubleshooting Small Office and Home Office (SOHO) Networks
SOME OF THE MAIN TOPICS IN THIS CHAPTER ARE
Computer Configuration Issues 951
Component Problems—You Can’t Get There from Here 956
Keeping Your Network Healthy 958
Wireless Networking Problems 959
Networks aren’t just for the office anymore, and they’ve quite literally come home in a big way. Although home networking was originally popularized as a means to share a single Internet connection, printer, or folder, today’s home networks do much more. Home networks are used to distribute digital media content between PCs or between a PC and a digital music player; transmit photos between a digital camera and a PC for editing; and enable console games and digital video recorders, such as TiVo and ReplayTV, to access online content.
Although it’s still possible to establish a direct parallel or serial port connection between PCs, those methods of communication are about the slowest you can achieve, and the limitation of just two computers leaves little room for growing your network. For a small office/home office (SOHO) network, you can use various technologies to create a network quickly and easily.
With the deployment of broadband technologies, such as cable and digital subscriber line (DSL) modems, the bandwidth is finally available to make connecting a home office to the Internet a practical solution.
Note
You can learn more about SOHO broadband technologies by reading Chapter 16, “Digital Subscriber Lines (DSL) Technology,” and Chapter 17, “Using a Cable Modem.” In addition, Chapter 20, “Faster Service: IEEE 802.11a,” and Chapter 21, “The IEEE 802.11g Standard,” discuss wireless standards that are frequently being used together on mediafriendly wireless networks. Dual-band wireless hardware runs streaming media content over the 5GHz, 54Mbps 802.11a network, and uses the 2.4GHz, 54Mbps 802.11g network for conventional printer, file, and Internet sharing.
See “Improving Network Performance with Dual-Band Wireless Technology,” p. xxx, to learn more about dualband 802.11a/802.11g network hardware. [Chapter 21]
The number of telecommuters—employees who work from home, as well as employees who travel frequently—has been on the rise. A large number of households now have more than one computer or printer, as well as an Internet connection. Because of these and other factors, the Internet is becoming as important to our economy as the telephone switched network (if not more important already). In fact, the rise of business and residential voice over IP (VoIP) service, which uses the Internet instead of the telephone network, is another way that the Internet is changing how we do business at home and at the office.
Another factor that has contributed to using the Internet as a means of communicating with a business network is the increasing use of Virtual Private Network (VPN) technologies, which are discussed in Chapter 46, “Virtual Private Networks (VPNs) and Tunneling.” By creating a secure communications path through the Internet, VPNs help reduce the cost of telecommuting, such as long-distance charges. Windows XP, Windows 2000 Server and Professional, and Windows Server 2003 all provide VPN solutions in the operating system, so the VPN option is not an extra expense to bear. Some routers also incorporate built-in VPN clients. And when it comes to Unix or Linux, you can pick and choose from a large number of VPN solutions.
SOHO networks usually are composed of only a few computers or other networked devices, so troubleshooting problems on this kind of network is a lot easier than trying to track down problems in a large network. Most of the hardware components are plug-and-play, and even software configuration is a lot simpler than it was a few years ago. However, no matter what kind of networked devices you have in your SOHO environment, invariably a time will come when a document won’t print, or a computer can’t connect to a resource on another system, and you’ll need to spend some time troubleshooting the problem.
Note
Appendix E, “Introduction to Setting Up a SOHO Network,” will help you better understand the concepts discussed in this chapter, and it is recommended that you read both of these chapters together. Each has information that will help you understand the concepts in the other. If you know how your SOHO network is set up and some of the basics about how it operates, you’ll be better trained to troubleshoot problems/solutions discussed in this chapter.
In this chapter, we’ll look at some common problems you might encounter and methods you can use to troubleshoot them.
Power Problems
As basic an issue as power might seem, it should be your starting point when you have a device that is not functioning correctly. For example, you might get up one morning and find that although your computer is working just fine, nothing prints. You check the printer and find that it’s turned on and has paper loaded; you just can’t figure out what the problem might be. Check your hub or switch. Has someone accidentally unplugged the AC adapter that powers the device? Most hubs have a power LED that indicates when the unit is powered up. If you have a power strip, check that too. It’s easy, especially in a small office where you don’t route cables through the wall, for something as simple as an unplugged device to cause problems. Of course, look to see that no one has switched the power strip to the off position.
The term power strip can refer to either a temporary switched power strip or to a true surge protector (also known as a surge suppressor). At a minimum, a surge suppressor prevents damaging voltage surges from affecting connected equipment. Some also filter out electrical noise and interference.
You should use high-quality surge suppressors to protect your SOHO network and other electronics around your home. A true surge suppressor is a UL 1449–rated device (check the packaging for the UL rating). Any surge suppressor that meets this standard is a very good one and offers a line of protection beyond what the power supply in your PC already offers. The only types of surge suppressors worth buying, therefore, should have at least two features:
Conformance to the UL 1449 standard
A status light indicating when the unit can no longer provide protection. It’s preferable to look for units that shut down power to the outlets to prevent devices from being damaged when the unit can no longer stop surges.
Other useful features to look for include
Increased spacing for AC/DC converters—Many peripherals, such as broadband and dialup modems and some types of printers, are powered by AC/DC converters (also known as power blocks or briquettes). Surge suppressors that provide extra spacing between outlets enable all outlets to be used, even when some are occupied by power blocks. When combined with a double-side design (in which both sides of a surge suppressor include outlets), wide spacing of AC outlets helps assure that every outlet is a usable outlet.
Surge suppression for data lines—If you have a dial-up modem, an all-in-one device, or a fax machine connected to a phone line, don’t overlook the possibility of phone line surges. Phone lines carry power (enabling the phone to be used during a power blackout), so they can also transmit a damaging surge to the modem or the server. Surge protectors with RJ-11 ports provide protection against phone line surges. A few surge protectors on the market now offer surge protection for RJ-45 Ethernet cables as well. Surge suppressors marketed for home theater systems often include surge suppression for RG-6 coaxial cable (used for cable modem, satellite TV, and cable TV).
Built-in circuit breaker—The breaker protects your system if it or a peripheral develops a short.
For greater protection against electrical problems, consider connecting each PC and network device (such as a broadband modem and router) to a battery backup (UPS) device. UPS devices are available from many vendors and are designed to provide a few minutes of runtime when the power goes out—enough time to close applications and shut down computers without losing data. Many UPS units feature signal lights to inform you of battery condition and whether your PCs are running on normal AC power or on battery power from the UPS. A single UPS can power a computer, a monitor, and typical external peripherals, such as a cable modem and router. However, printers should not be connected to a UPS—they draw too much power, and are not mission-critical devices.
For more information on UPS devices, see Chapter 5, “Protecting the Network: Preventive Maintenance Techniques.”
Finally, if you are having power problems with all the computers on your network, check the fuse box or power panel in your home or office to be sure that the fuse or circuit breaker at that point hasn’t disconnected the power.
If computers or other devices on a SOHO network are malfunctioning, don’t overlook the possibility that they are connected to poor-quality or incorrectly wired outlets. An inexpensive AC circuit tester such as the one shown in Figure 50.1 can be used to determine if the electrical outlets in your home or office has been configured properly. This tester uses signal lights to indicate common wiring problems, such as open ground and reversed wires.
Figure 50.1. This circuit tester indicates the outlet is wired correctly.
Another type of electrical tester known as a multimeter can be used to test electrical outlets for correct AC voltage levels. A typical shirt-pocket multimeter is shown in Figure 50.2. Multimeters can also measure DC voltage cable continuity and perform other tests. See the multimeter’s instruction manual for details and testing methods.
Figure 50.2. A typical multimeter. Use the probes at right for testing outlets and devices.
Computer Configuration Issues
If you use a broadband connection to the Internet, you’ll probably have a switch/router appliance connecting your small LAN to the cable or DSL modem. These inexpensive devices allow your LAN to share a single Internet connection (that is, a single IP address) on the Internet, while providing for separate addresses for each computer on the LAN.
DHCP (the Dynamic Host Configuration Protocol) allows the router/switch to automatically configure your computer with the network addressing information it needs when it boots up. When you add a new computer to the LAN, you need to be sure that it’s configured to use DHCP. Otherwise, if you’ve configured a static address on the computer, you need to be sure that the following are true:
The address is compatible with the addresses of other computers on your network.
The address is not already in use by another computer on the network.
Tip
Although you might consider yourself a network guru just because you have a network at home, don’t outsmart yourself. If you decide to assign static IP addresses to some computers in your network, such as a server, then be sure to enable your DHCP service to use an address range which doesn’t include that address. Or, if your switch allows, enter a record for the static address. This can be useful when you’re connecting to the Internet yet maintaining an internal Windows domain-based network.
Recent Windows versions make it easy to configure DHCP and to verify your settings. For example, Windows XP uses this method to configure a LAN connection to use DHCP:
1. Select Start, My Network Places, View Network Connections. If My Network Places is not visible in the Start menu, open My Computer and select it from the pull-down menu.
2. Right-click your local area connection and select Properties.
3. Scroll down in the Components section of the properties sheet shown in Figure 50.3, highlight Internet Protocol (TCP/IP), and click the Properties button.
Figure 50.3. Select Internet Protocol to troubleshoot network address issues.
4. The Internet Protocol (TCP/IP) Properties sheet pops up, as shown in Figure 50.4. If you are using DHCP, be sure that the Obtain an IP Address Automatically option is selected. Unless your Internet provider has told you otherwise, the Obtain DNS Server Address Automatically option should also be selected.
Figure 50.4. This system gets its IP address from a DHCP server, which might be built into a router, a wireless Access Point or gateway, or a computer running Internet Connection Sharing.
5. To configure a computer with a static IP address, select Use the Following IP Address. You must then manually input the IP address, subnet mask, default gateway, preferred DNS server, and alternate DNS server. Figure 50.5 shows an example of a static configuration. Another way to view user-assigned (static) or server-assigned (DHCP) IP address information is to run IPCONFIG/ALL from the command line, as described in step 7.
Figure 50.5. An example of static IP address configuration.
Tip
If you need to manually configure one or more stations on your network to use a static IP address, you can use IPConfig (Windows 2000/XP) or WinIPCfg (Windows 9x/Me) on another station on the same network to determine the IP addresses for the default gateway and DNS servers. Any IP address you assign to a station must use the same three initial numeric groups, and specify an unused number for the last group. For example, if your network has a default gateway of 192.168.0.1, stations on the network can use IP addresses 192.168.0.0–192.168.0.254. If some stations use DHCPassigned IP addresses, make sure that stations with user-assigned IP addresses use IP addresses that are not assigned by the DHCP server. One way to do this is to specify a limited range of IP addresses that the DHCP server on your network can assign. Then, specify addresses outside that range.
6. If all looks okay in the configuration screens, check out what address your computer is actually using. Choose Start, Programs, Accessories, Command Prompt for Windows 2000, Windows XP, or Windows Server 2003; or Start, Programs, Command Prompt for earlier versions of Windows.
7. From the command prompt, issue the command IPCONFIG /ALL for Windows NT/2000/XP or Windows Server 2003 operating systems (you can use WINIPCFG to find the same information for Windows 95/98 or Windows Me). The response to this command will include a lot of information, so look for the IP address and the subnet mask. Refer to Chapter 27, “Troubleshooting Tools for TCP/IP Networks,” for examples. All computers on the network should be part of the same network or subnet.
It doesn’t matter if all the cables are connected to the hub or switch and each computer’s network card if you have misconfigured IP addresses or subnet masks. For example, a computer with an IP address of 192.168.0.34 is not going to talk to a computer with an address of 172.16.0.23, no matter how long you try, unless you go through a router that has been configured to pass this information. The network adapter card detects the data you try to send back and forth, but because the protocol stack knows that it’s destined for a different network, those packets are ignored and never passed up to the Application level.
Figure 50.6 shows an example of using a switch/router to connect to the Internet through a cable or DSL modem.
Figure 50.6. Connect to the Internet using a cable or DSL modem and a router/switch. Note that the IP address for Computer C is not valid on the LAN and can’t pass through the switch/router.
In this example, the Internet service provider (ISP) has assigned an IP address to your connection (296.34.81.5). This might be a permanent assignment (known as a static IP address) or the ISP might periodically change the IP address. In either case, you have one IP address. Because you have more than one computer, you went to the local computer store and bought a small switch/router designed to work with broadband connections. Note that the switch/router is plugged into the broadband modem using one port (usually known as the WAN port), and stations connecting through the switch/router plug into LAN ports or use wireless connections. To keep track of both connections, the switch/router uses a different address on the port that connects to your LAN. This address is known as the default gateway IP address.
In this example, the IP address is 192.168.0.1. The switch/router uses the address range of 192.168.0.0 through 192.168.0.254 to allocate IP addresses to computers on the LAN. In reality, most routers are configured to provide IP addresses to only a fraction of the full range. In this example, we assume that the router is configured to use DHCP to provide IP addresses to 10 computers (192.168.0.100– 192.168.0.109). Other IP addresses in this range can be used for static IP addresses. In Figure 50.6, Computer A has a server-assigned IP address, while Computer B has a static (user-assigned) IP address. Note that both addresses are in the same 192.168.0.x range as the LAN (default gateway) address used by the router.
Note that Computer C cannot connect to other computers on the network and cannot connect to the Internet, either. It has a static IP address range in the 172.16.0.0–172.16.0.254 range, which is not the same range of IP addresses used by other computers.
Because the router has two addresses (a public and a LAN IP address), it is able to determine what traffic is local and what traffic is bound to or from the Internet. When Computer A (192.168.0.100) on your network wants to send or receive data to or from the Internet, the switch/router knows that the IP address of the Internet server (296.34.81.5) is different from the LAN address (the 192.168.0.x address space). Thus, Computer A knows that it must send the data packet to the default gateway, which is the switch/router (192.168.0.1). When the switch/router receives the data packet, it substitutes its own valid Internet address (296.34.81.5) in the packet header and sends it to the Internet through the broadband modem. When a response is received back from the Internet connection, the switch/router removes the 296.34.81.5 address from the packet header and puts Computer A’s address (192.168.0.100) in the header so it can be delivered to Computer A. Traffic generated by or destined for Computer B works the same way, except that its address (192.168.0.34) is used.
The important thing to keep in mind here is that addresses used inside the network are not valid on the Internet. The switch/router must use sleight of hand to act as a “man in the middle” for you so that, although you have multiple computers on your LAN, the switch/router makes the cable or DSL modem think you have only one. The switch/router keeps track of which computer on the LAN sends out requests and makes sure that packets are routed back to the correct computer.
Note
The addresses chosen in the example shown in Figure 50.6 are based on the most common reserved IP address spaces used by routers sold for SOHO networks. You can learn more about reserved IP address spaces that you can use in your local network but that are not valid on the Internet. Chapter 24, “Overview of the TCP/IP Protocol Suite,” covers this topic in detail.
When Computer A wants to talk to Computer B, it compares the address of Computer B (192.168.0.34) with its own address. Because the address falls in the same network address space, it doesn’t send the packet to the default gateway. Instead, it just broadcasts a packet on the LAN knowing that Computer B will see the packet and pick it up.
So far everything is working as it’s supposed to. However, let’s suppose you just brought a computer from work to your home office (Computer C) and plugged it into your network. At work, the computer had been configured with a static address of 172.16.0.23. When you try to send or receive data from Computer C, nothing happens because of the following:
Computer C has an IP address that does not match the addresses on the LAN, so the other computers just ignore the packets that Computer C sends out.
Computer C was configured at work to use a different default gateway address, so it can’t even get a packet to go through the router/switch.
The point is that if your switch/router allows for DHCP and you set up each computer to use DHCP, things should work just as you expect. If you try to mix and match computers with different subnets on the same LAN, you’re going to have trouble. If you need to use static IP addresses, make sure you never use an address that could also be assigned by the DHCP server in the router. If two devices have the same IP address, neither one will work.
Try using the ping command (described in Chapter 27) from another computer to determine whether it can bounce packets off another address on your network. If not, you probably have unplugged the computer from the network (either at the network card end or at the switch/router or hub), or your firewall software might not be configured to permit connections from another station on the network.
Component Problems—You Can’t Get There from Here
Just as in a large corporate network, you might have a problem with one or more components that make up the network. Network cards go bad, as do hubs and switches (and even individual ports on a hub or switch). Always keep handy the minimal documentation that comes with your computer(s), network card, hub, switch, router, and other devices so that you’ll know what the LEDs mean when you start troubleshooting.
For example, most network adapters have two LEDs you can examine. One is called the link LED and the other is used to indicate activity on the network. If both of these LEDs are off, you might have a bad network card. Before you make that assumption, however, try moving the cable that plugs the card into the hub or switch/router to a different port and see whether that makes a difference. Check the LEDs on the hub or switch/router to determine whether they have link or activity LEDs. Try switching the patch cable that runs between the network adapter and the port on the switch. Above all, read the documentation to understand what the LEDs mean for your specific product.
These same signal lights are also present on switches, including routers with integrated switches. Routers also have additional signal lights to indicate WAN traffic (traffic moving to and from the broadband cable or DSL modem) and diagnostic lights. See your router’s documentation for details.
Another thing to think about is that many small hubs or switches have an “uplink” port that allows you to connect the device to another one when you want to expand your small LAN. The pinout for this port is not the same as it is for the other ports. The transmit and receive pins are swapped. If you need to plug a computer into an uplink port, you can usually do so, but there will probably be a small button or switch you need to use to change it from an uplink port to a standard port.
Secure Those Cables!
A common problem with small offices or home offices is that you are not using a structured wiring plan. That is, you just string cables from here to there and plug things in. If you have a twisted-pair network cable lying on the floor near your desk, use tie-wraps, scotch tape, or anything else that you can to make sure that the cable doesn’t just lie on the floor where you can roll over it with a chair. Even stepping on a twisted-pair network cable can be enough to cause it to have problems carrying the network signal. Secure those cables so that they aren’t mangled by accident.
If you can’t hide your cables from foot traffic or other hazards, consider using cable organization devices such as wire ducts, raceways, cord protectors, and so forth. Cableorganizer.com is a leading company in cord and cable management.
Note
A friend of mine had a pet rabbit at home that was occasionally let out of the cage. Rabbits, in case you don’t know, like to chew on just about anything (my friend no longer has the rabbit). Be sure to keep your network cables (not to mention electrical cords) safe, even from your pets!
If you suspect a problem with the cable, trace it from the network card back to the hub or switch/router to be sure that it hasn’t been damaged. Never try to “stretch” a cable or pull too hard on it when you are moving things about. This too can damage the cable and cause it to generate so many errors that the network becomes unavailable to the attached computer.
Note
If your service provider is using DSL, you might have to connect a small device to your telephone outlet known as a microfilter before you can plug in a telephone. This device prevents telephone interference from causing problems with the frequencies used on the copper wire by the DSL service. And the reverse is also true. These filters can keep the DSL frequencies from interfering with and degrading the voice channel. Not all DSL services require this sort of device. If your service requires microfilters, be sure you obtain another microfilter when you buy a new phone for a different room. Don’t just plug in the phone and expect all to be well. A ringing phone or a phone off the hook can cause enough interference to make the DSL connection sporadic or nonfunctional for this kind of connection.
Firewall Problems
If you have installed a router/switch device between your network and a broadband Internet connection, be sure to read the manual thoroughly and understand how the device should be configured. Many come with default settings, but you need to fill in some information, such as the address of the broadband link, if your service provider gives you a static address. In most cases, the provider will be using DHCP also, so you won’t have to make any changes. If you do have to make changes, write them down and keep the information handy for later troubleshooting efforts.
Tip
Most routers are configured through a web browser. They contain a web server that displays information and configuration data in your web browser. Print the screens or capture them using Save As Web Archive (with Internet Explorer) for easy reference to current settings. Be sure to write down changes you make to the default password used to guard against unauthorized tinkering.
Earlier in this chapter, you read that it’s not a good idea to mix computers you use for play with those you use for business on the same network. If you do, you are just asking for trouble. If you play Internet games—those that allow you to interact with other users playing the same game on the Internet—you might be instructed to change the port settings on a small switch/router that also functions as a firewall. If you start playing around with opening, disabling, or forwarding ports, keep track of the changes you make. If something stops working after you’ve made a change, undo the modification and see whether the changes you’ve made have caused the problem.
Some users prefer to use the demilitarized zone (DMZ) option as an alternative to fiddling around with router settings to make online gaming possible (see Figure 50.7).
Figure 50.7. Using the DMZ Host setting in a router is an easy but dangerous way to enable online games to play on a particular IP address on the network.
Caution
The easiest, but most dangerous way, to prevent your router from interfering with an online game is to use its DMZ feature. When you enable DMZ, you specify the IP address of the computer that will be fully exposed to the Internet. Make sure you use the IP address of the correct computer. That computer should also be equipped with up-to-date antivirus definitions and a software firewall because the router is no longer going to protect it from online hazards.
If possible, use the port forwarding or other features in your router that are designed to support online gaming as an alternative to using DMZ. You need to know the settings required for a particular game, but avoiding the use of DMZ is safer.
Remember that the firewall capabilities of a small switch/router are minimal and are designed to protect you from simple attacks from the Internet. It might be that the default settings are very stringent, and if you end up making changes that relax the firewall settings, you might also be opening a door that can allow bad things into your small LAN.
For more information about how firewalls work and the features that are important, see Chapter 45, “Firewalls.”
Keeping Your Network Healthy
Another good reason to keep your entertainment computers separate from your business LAN is that you don’t want to be surfing the Web, find a neat program, and download a virus or some other bad program that will start to eat up things in your network. This is yet another reason other people shouldn’t be using your business computer to access the Internet. Additionally, if you have children who want to use the Internet, you might want to buy them their own computer and provide a separate Internet connection. The shorthand is like this: Play games on your play computers; do business on your business computers. If at all possible, it’s not a bad idea to adopt this policy. With computer prices falling and the fact that many people keep older computers after upgrades, this may be more feasible than ever.
And, of course, because business is business, back up your files on a regular basis. Above all, it’s worth the cost to buy a good antivirus software package and keep it updated. The cost is a tax deduction and it will save you a lot of grief if something bad does get loose in your network.
For the safety of your network, a good antivirus program should be used to scan all disks on all computers on your LAN on a very frequent basis—such as nightly when you are asleep. A good antivirus program should also download updates (new virus definitions) frequently. Daily updates are recommended. If you hear of a new virus outbreak, you should immediately check for updates manually.
Keep in mind that if you don’t keep your virus definitions up-to-date, then when one gets loose in even a large network, much less a small one, it can wreak havoc as it quickly spreads.
Lastly, a good antivirus program should detect malicious attachments when you are sending and receiving email, and should check removable media (such as a floppy disk) and block you from copying files if the removable media contains a virus or some other threatening program.
Unless your antivirus program was part of a security suite, you might not have anti-spyware software. Make sure you obtain and use two or more anti-spyware programs. Unlike antivirus programs, which can conflict with each other, it’s okay to install more than one anti-spyware program.
Wireless Networking Problems
The newest, latest, and maybe greatest approach to SOHO networking environments is to remove the cables altogether. It’s now quite inexpensive to buy a small wireless Access Point (AP) and install wireless network cards in the computers in your small or home office. This allows you, for example, to use a laptop and take it from the living room to the kitchen to the basement, or wherever you feel most comfortable working. Heck, if it’s a nice day outside, you might as well take the laptop out to the deck in the back yard, work from there, and get a tan at the same time!
Wireless is a fairly big topic; for more information on wireless networking solutions, see Chapters 18–23.
You should keep a few things in mind when using wireless networking, however. Both in a small office and at home, you’re likely to have a microwave oven sitting around somewhere. Although this is usually not a problem, it is possible for a microwave oven to interfere with the wireless transmissions of your network. This should be easy to troubleshoot. Just turn it on and determine whether the computers in your LAN can still talk to each other. Check for signal strength and speed; even if you can connect, your range or speed might be limited while the microwave is running. Another problem is that wireless networking is bounded by how far you can be from the AP. Although you might be able to communicate with the AP from the living room, the signal might not reach the basement, or it might not be strong enough to penetrate the brick wall that separates the backyard deck from the AP. Experiment to see whether moving the computer closer to the AP fixes the problem. If it does, you can always buy one or more APs, place them in strategic locations around the home or office, and use ordinary twisted-pair cables to join the APs to a switch/router that connects you to the Internet. Some vendors offer APs that can be used as repeaters. Using a repeater is useful if you cannot easily run UTP cables between one AP and another. Note that a repeater or an AP/repeater is made to work with certain models of APs from the same vendor only. Although you can mix and match brands of routers, APs, and adapters, the AP and repeater must be able to talk to each other.
If you cannot get a repeater or don’t want to worry about configuring yet another wireless device, consider these range and speed boosters:
Replace conventional antennas with high-gain or directional antennas. Most wireless AP and router vendors now offer these for at least some of their product line.
Switch from a conventional 802.11g router to a router that features multiple in/multiple out (MIMO) antenna technology.
Switch from conventional 802.11g adapters to those that support MIMO. Some types of MIMO hardware provide better range, even when connecting to standard 802.11g routers. Learn more about how MIMO boosts range (and might also boost speed) in Chapter 21.
Note also that other wireless devices, such as 2.4GHz cordless telephones or 2.4GHz wireless security cameras like the ones on those annoying pop-under ads, can interfere with wireless networks. This is a simple thing to troubleshoot. Just make a phone call and watch file transfers from one computer to another creep to a halt.
For wireless connections, be sure to use the management application that allows you to check/configure the Access Point, and do the same for each wireless network adapter in the network.
Before you call your cable or DSL provider, you should carefully go over every aspect of your LAN and determine how each computer is configured. ISPs don’t make a lot of money off individual customers—it’s the large aggregate of happy customers who have no problem that pays their bills. A single call from you might negate an entire year’s worth of what you are paying them.
So, to be a nice player, check such things as network addressing, cables, and other things mentioned in this chapter as a start. For example, the first thing to do is take an adapter that is known to be good (that is, it’s working on one computer) and substitute it for one that you suspect is bad. Check the adapter configurations on both computers. If you suspect that a network cable is the problem, swap it with one that is working.
This procedure of swapping parts that are known to be in good working order might be the quickest way to solve the problem. Remember that if the problem does lie on your end of the line, it can likely be fixed more quickly if you find it yourself than if you have to wait days for the provider to send someone to your site.
When All Else Fails
If you’ve tried everything in this chapter and you can send and receive data on your LAN, but not to or from the Internet, there is an important tool that can help solve this problem. Every office (and most every home) has this tool: the telephone. Pick it up, call your ISP, and find out whether the problem is on its end. Simply dial the ISP’s customer service line and be persistent.
Provided that you have thoroughly checked out your end of the connection first, never take “it’s not our problem” for an answer. If it was working and now it’s not, your ISP should be able to at least troubleshoot the problem from its end. If the problem can’t be solved on the phone, request that the ISP send someone out to prove to you that the cable or DSL modem is working as it should. The problem today is that ISPs that provide broadband access to the Internet are growing so fast that it’s hard to find qualified technical personnel to troubleshoot the customer problems that happen. It’s easier to make you struggle through level after level of automated touch-tone response menus and then let you talk to some script-reader who just screens calls, looks up things in a database, and spits out a canned answer. Be sure you get through to someone who knows his stuff and can get the problem fixed.