Section 7.3. Setting Up a Network

7.3. Setting Up a Network

Setting up a peer-to-peer network in Windows Vista is quite straightforward. This section assumes that you have a broadband connection (such as a DSL or cable modem) and that you want several PCs to share that Internet connection as well as to share resources with one another.

You'll need to buy a router, which is commonly available for between $50 and $100, depending on its capabilities. Your best bet is to buy a wireless router, as described earlier in this chapter. Wireless routers include Ethernet ports (most commonly four) so that you can use them to network both wired and wireless PCs.

Make sure that each PC has a wired or wireless network adapter. (See the entry for "NIC," in the "Networking Terminology" section, earlier in this chapter.) Virtually any desktop PC you buy should already have an Ethernet adapter built in, and laptop PCs almost always include both built-in wireless and Ethernet adapters. If not, though, you can buy wireless adapters as PC cards for laptops, PCI cards for desktops, and USB adapters for either desktops or laptops. If you're buying new adapters, make sure that your wireless router and all the wireless adapters follow the newer, faster 802.11g wireless standard, not the older, slower 802.11b standard.

Keep your eye on the 802.11n standard. If it ever gets final certification from the body that governs WiFi connections, it is worth considering because of its high speed. However, steer clear of any equipment labeled "pre-n" because that means it has been built before the standard has been formally ratified, and it may not be compatible with the standard, or with other 802.11n equipment, when the standard is finally approved.

Follow the instructions of the router manufacturer for installing the network. Take note of the IP address range used by your router (such as 192.168.0.x, where x is between 1 and 254). As a general rule, though, you need to first install all the adapters or wireless adapters on all the PCs. Then connect the router to your DSL or cable modem using an Ethernet cable. Make sure you use the correct port on the router. It may be labeled as "Internet" or "WAN," and it may be set apart from the other ports on the router in some way. For example, in some Linksys routers, the port for connecting to a DSL or cable modem is outlined in blue, and the ports for connecting to PCs are outlined in yellow.

Next, connect one of your PCs via an Ethernet cable to the router. This will be used to configure the router. Follow the manufacturer's instructions for doing so.

Many routers come with an extra CD or installation disk. Keep the disk handy, but note that you don't always need this disk in order to set up your router. Not uncommonly, the disk comes with trial versions of firewalls, antivirus software, and other software that will install automatically on the PC that you are using to set up the router. Install from the CD only the software you know you want to use.

After that, configure each individual PC to connect to the network, either via Ethernet cables or wirelessly. Details on how to do that are covered in "Connect to a network," later in this chapter.

Once you've configured the PCs, they should all have Internet and network access. It's a good idea to test each PC's connection using Ping (see "Ping," later in this chapter). By default, your router will assign IP addresses in the following way: the first computer will be 192.168.0.2 (.1 is usually reserved for the router), the second will be 192.168.0.3, and so on.

The first three bytes of the numbers may vary from router to router (see "Understanding Private and Public IP Addresses," later in this chapter), but the last byte will progress in the same manner. So, you may need to replace the 192.168.0 portion with the numbers from the IP address range you noted when you set up your router. See "Network Connection Status," later in this chapter, to figure out your current IP address.

Assuming your network is similar, pick a computer (or your router), go to a command prompt, and type ping address, where address is the IP address of the other computer. For example, from the 192.168.0.2 computer, you would type:

 ping 192.168.0.1 

If the network is working, you'll get something like this:

 Pinging 192.168.0.1 with 32 bytes of data: Reply from 192.168.0.1: bytes=32 time=7ms TTL=128 Reply from 192.168.0.1: bytes=32 time=1 TTL=128 

On the other hand, if you get this result:

 Pinging 192.168.0.1 with 32 bytes of data: Request timed out. Request timed out. 

it means the network is not functioning.

If your network is functioning, you can proceed to set up the various services you need, such as file sharing, printer sharing, and so on. You can also use ping to test your connection to the Internet, for example, by typing:

 ping www.oreilly.com 

If you receive a Request timed out response, try pinging another web site, because the issue could be caused by the web site rather than your own network.

7.3.1. What to Do If Your Connection Doesn't Work

If all goes well, you should be able to set up a network without problems. But if you do run into trouble, follow these tips to help you get around most of the common hurdles you'll encounter when setting up a LAN:

• If you're setting up a wireless network, a number of things may cause connection problems. Your PCs may be too far away from the router, or they may be in a "dead spot" that gets bad reception. Try moving your PCs or your router until you get better reception. Try placing the router in a central place in your house or business or extending your wireless network's range with multiple access points configured for Wireless Distribution System (WDS) operation.

• Some home devices can interfere with wireless networks, such as microwave ovens and cordless phones. Try turning them off to see if that solves any interference problems.

• If the problem is with wired PCs, check your cables and make sure the appropriate lights are on. If you're unsure which lights to look for, try unplugging a cable from a device. If a light on the device goes out and then goes back on when the cable is plugged in, that's the light you're concerned with. Such lights are often labeled "Link."

• If you can ping the PCs on your network but you do not have Internet access, it means that your network is working properly but there is a problem with its connection to the Internet. Make sure that your cable or DSL provider has turned on your Internet connection and that it is visible to them.

• Run the Diagnose and Repair Wizard (Control Panel Network and Internet Network and Sharing Center Diagnose and repair). That should track down the cause of the problem and fix any issues, or recommend fixes.

• Windows Vista is designed to implement most changes to the network without restarting. However, if you encounter problems, try restarting one or all of your machines to force them to recognize the new network.

• Make sure no two computers on your network are attempting to use the same computer name or IP address.

• Make sure you have the latest drivers for your network adapter or, if you have a built-in network adapter, for your motherboard or PC; check with the manufacturer for details.

• Right-click the connection icon in the Network Connections window and select Diagnose.

These instructions assume the network settings for your connections haven't been tampered with. If you suspect that your settings might be wrong, open Device Manager, right-click the entry corresponding to your network adapter, and select Uninstall. (Note that it's not necessary to physically remove the device from your system.) When you restart Windows, the adapter will be redetected and the drivers will be reinstalled.

7.3.2. Understanding Private and Public IP Addresses

Any computer on the Internet or a LAN must have an IP address in order to be connected and to use all its services. (An exception is if you are connected to an older-style network that is not based on IP, but this is extremely rare these days.) But because of the explosion of the Internet and networks, including home and small-office networks, there are not enough IP addresses to go around for everyone who wants to connect.

To solve that problem, home networks and small-office networks use a technique called Network Address Translation (NAT). With NAT, each PC on the network receives its own private IP address that can be used only for communicating internally on the network. The network, as a whole, has a single public IP address used on the Internet. So a PC on the internal network may have an IP address of 192.168.1.103, but to the Internet, its IP address may be 66.30.117.9.

How does this magic happen? The home router has the IP address of 66.30.117.9. Every PC that connects to the Internet uses that IP address. But inside the network, the router uses DHCP to assign each PC an internal, private IP address, such as 192.168.1.100, 192.168.1.101, and so on.

Several blocks of IP addresses are assigned to be private IP addresses, including 192.168.0.0 to 192.168.255.255, which are the private IP addresses commonly used by home and small-office routers. That means the PCs on your network can use any IP address in that range, and your neighbor's PC can use any IP address in that rangein fact, anyone with a private network can use any IP address in that range. There will not be a conflict between you and others using the same IP address because those IP addresses are internal to the networks, are private, and are not used on the public Internet.

Other private IP addresses include 10.0.0.0 to 10.255.255.255, 172.16.0.0 to 172.31.255.255, and 169.254.0.0 to 169.254.255.255.

NAT also provides some Internet security. It makes it more difficult for malicious users to directly connect to or attack a PC on a network that uses NAT because the PC's IP address is not a public IP address, making direct "end-to-end" connections more difficult.

7.3.3. Networking Windows Vista with Windows XP and Other Windows Versions

If you have a network that combines Windows Vista PCs with PCs that have earlier versions of Windows, you may notice anomalies and problems. Windows Vista includes new technologies that make networking easier than previous Windows versions, notably the new Link Layer Topology Discovery (LLTD). LLTD allows Windows Vista to automatically detect wired and wireless devices attached to the network, obtain and display information about those devices, and diagnose problems with them, such as low bandwidth in home networks or weak wireless signals.

The devices have to support LLTD, but many existing devices are upgradeable via firmware, and many new devices include built-in LLTD support.

The problem, though, is that older versions of Windows do not include LLTD. So those PCs are not supported as well as Windows Vista-based PCs. For example, when you view a network map (see "Network Map," later in this chapter, for details), the PCs may take a very long time to show up on the mapeven as long as 15 minutes. In addition, they generally appear at the bottom of the screen, but not as part of the map itself.

At the launch of Windows Vista, Microsoft was slated to issue a patch that will add LLTD capabilities to Windows XP PCs. But it currently has no plans to add LLTD to any other earlier versions of Windows.

7.3.4. Implementing Network Security

Security is a very real concern for any computer connected to a network or the Internet. There are three main categories of security threats:

A deliberate, targeted attack through your network connection

It's possible for a so-called hacker to obtain access to your computer, either through your Internet connection or from another computer on your local network. Ironically, this is the type of attack most people fear, but realistically, it is the least likely to occurat least where home and small-office networks are concerned.

An automated invasion by a virus or robot

A virus is simply a computer program that is designed to duplicate itself with the purpose of infecting as many computers as possible. If your computer is infected by a virus, it may use your network connection to infect other computers; likewise, if another computer on your network is infected, your computer is vulnerable to infection. The same goes for Internet connections, although the method of transport is typically an infected email message or an application that has been downloaded from a malicious source. This is why you need to be careful about what you get from peer-to-peer file-sharing systems; some attackers will share a file claiming to be one thing, while it's actually malicious software in disguise.

There also exist so-called robots, programs that are designed to scan large groups of IP addresses and look for vulnerabilities. The motive for such a program can be anything from exploitation of credit card numbers or other sensitive information to the hijacking of computers for the purpose of distributing spam or viruses.

A deliberate attack by a person sitting at your computer

A person who sits down at your computer can easily gain access to sensitive information, including your documents, email, and even various passwords stored by your web browser. An intruder can be anyone, from the person who steals your computer to a coworker casually walking by your unattended desk. Naturally, it's up to you to determine the actual likelihood of such a threat and to take the appropriate measures.

There are a variety of ways to protect your network from attack, including using the Windows Firewall, Windows Defender, the Security Center, and more. For details, see Chapter 8, in particular the "Internet Security" section.

7.3.5. Setting Up Wireless Encryption

If you have a wireless network, it's a good idea to use encryption to protect it. If your network isn't protected by encryption, passersby may be able to easily connect to it or use a network "sniffer" to read all of its traffic.

Setting up wireless encryption is a two-step process. First, you enable wireless encryption on your wireless router, and then you configure every wirelessly equipped PC on your network to use that encryption.

If you have a network that includes both wired and wireless PCs, you won't need to configure your wired PCs to use encryptionthey don't use encryption because their data is not sent out over the air.

Every router manufacturer has a different method for configuring wireless encryption, and it even varies from model to model of the same manufacturer. So read your router's documentation for how to configure yours. The instructions that follow are for the Linksys SRX400 router.

First, log in to your administrators screen, then select Wireless Wireless Security. From the Security Mode drop-down menu, select the encryption method you want to use. WPA/WPA2 Personal is a good choice for a home or small network. WEP is a less powerful encryption method and is not as good a choice.

To use WPA/WPA2 Enterprise encryption, you'll need a separate authentication server called a RADIUS server.

Fill out the form that appears (Figure 7-5). Enable WPA and WPA2, and choose the kind of encryption algorithm you want to use. Then type in a personal "key," which is a password between 8 and 63 characters long. The longer the key, the more secure the network. Write down the password, because you'll need it in order to configure encryption on each of your wireless PCs. Click Save Settings when you're done.

Figure 7-5. Setting up encryption on a Linksys router

Now you have to go to each of your wirelessly equipped PCs and match their encryption information and key to the routers. Go to Control Panel [Network and Internet] Network and Sharing Center View status, and click Wireless Properties. Click the Security tab. The screen shown in Figure 7-6 will appear.

Figure 7-6. Setting up encryption on your PC

Select the Security type and Encryption type that match the types you chose on your router, and in the Network Security key field, type in your password. Click OK. Your PC will now be able to connect to the router using encryption.

7.3.6. Sharing an Internet Connection with Internet Connection Sharing

There is a way to share a single Internet connection among multiple PCs without using a router to connect to the Internet. It's called Internet Connection Sharing (ICS). In ICS, a single computer with an Internet connection acts as a gateway, allowing other computers on the LAN to use the connection. The computer that is connected directly to the Internet is called the host; all the other computers are called clients. It's usually best to use a router to provide shared Internet access, but if you prefer, you can set up a network using two PCs, one of which (the host PC) is connected to a broadband connection (such as a cable/DSL modem or an Ethernet connection in a hotel room). That PC can share the broadband connection to a second PC using a second Ethernet port or its wireless card.

To get ICS to work, you'll need the following:

• At least two computers, each with an Ethernet or WiFi adapter properly installed and functioning. It is assumed you've already set up your local network, as described in "Setting Up a LAN," earlier in this chapter. If you connect the host PC to a hub instead of directly to another PC, your Internet connection can be shared with as many clients as your LAN will support.

• One of the computers must have an Internet connection properly set up. The instructions that follow assume that the computer handling the Internet connection is running Windows Vista.

• If your Internet connection is provided by a router or you've allocated multiple IP addresses, you don't need ICS.

• If you're sharing a DSL, cable modem, or other high-speed, Ethernet-based Internet connection, the computer with the Internet connection must have two Ethernet adapters or one Ethernet and one WiFi adapter. See Figure 7-3 for a diagram of this setup.

The first step in setting up ICS is to configure the host, the computer with the Internet connection that will be shared:

1. Open the Network Connections window (Control Panel Network and Internet Network and Sharing Center Manage network connections). Here, you should have at least two connections listed: one for your Internet connection and one for the Ethernet adapter connected to your LAN. If theyre not there, your network is not ready; refer to the earlier topics in this chapter and try again. The host must have two working adapters, so if a PC has only one adapter, it cannot be a host.

2. Right-click the connection you want to share. (It will be the adapter that will be used for your Internet access.) Click Properties.

3. Select the Sharing tab (Figure 7-7), and then check the box next to "Allow other network users to connect through this computer's Internet connection." You can also allow other network users to control or disable the shared Internet connection. Click OK when you're done.

Figure 7-7. Enabling Internet Connection Sharing via the Sharing tab of a network connection's properties

The next step is to configure each client computer to use the shared connection. See "Connect to a network," later in this chapter, for details on how to set up an Internet connection for each PC. They must be set up to get an IP address automatically.

7.3.7. Setting Up a Bluetooth Device

Bluetooth is a wireless networking technology used primarily to connect devices and PCs over short distances. It is commonly used in cell phones, PDAs, and even mice, keyboards, and printers.

To set up a Bluetooth device, you'll need a Bluetooth adapter for your PC. The adapter will allow your PC to wirelessly connect with a Bluetooth device. If you don't have a Bluetooth adapter already, buy one and plug it into your USB port. Windows Vista will recognize the adapter and install it via a wizard.

Next, turn on the Bluetooth device and make it discoverable. Doing this will allow it to communicate with your PC. The way you make a device discoverable varies from device to device, so check the device's documentation or the manufacturer's web site.

Now go to Control Panel [Hardware and Sound] Bluetooth devices. Click Add, and follow the directions for connecting the device to your PC.