36. Wireless Networking

With the rapid growth of wireless networking has come evolving standards. The 802.11 series of standards was created by the networking industry to ensure hardware and software interoperability among wireless networking vendors. The current state-of-the-art standards 802.11n and 802.11ac are important steps forward for wireless performance and reliability, and we’re sure that network industry gurus are hard at work at whatever’s coming next.

And while people have been using cellular telephone networks to get data service for mobile devices for some time, the software for making and managing these connections was vendor specific and could be cumbersome to use. Today (thanks largely to Apple’s iPhones and iPads), consumers have come to expect seamless, effortless, and ubiquitous data service, and so Microsoft has integrated cellular data into the built-in, native networking stack in Windows 10. If you use cellular (for example, 3G, 4G, or LTE) data service on your Windows 10 device, you’ll be able to manage it using the same control panels we describe in this chapter. Configuration might still be vendor specific, but your vendor will help with this, and it’s not something you’ll have to do on a day-to-day basis.

This chapter shows you how to use infrastructure networks that have already been set up. We also discuss joining an ad hoc network for quick file sharing between a group of computers at, for example, a meeting.

For information on setting up a new wireless network for your home or office, see “Installing a Wireless Network,” p. 390.

To prevent random, unknown people from seeing your shared resources, the Network Location feature keeps track of the identities of various networks to which you attach, and it lets you designate whether each one is safe for file sharing. There are actually three location “types”: Public network, Private network, and Domain (corporate) network. In more detail, the standard types are as follows:

Public network—A network where other computers and users can’t be trusted. The Public network location should be selected for any network link that is directly connected to the Internet without an intervening router or hardware firewall; a network in a cafe, airport, university, or other public location; or a home or office that you are visiting. When you designate a network as a Public network, Windows file and printer sharing is blocked to protect your computer.

Private network—A network at home or work that is trusted to be secure. Either it has no Internet connection or its Internet connection is protected by an external firewall or a connection-sharing router. In addition, you trust all the users and the other computers on the network to access files and printers shared by your computer (with or without a password, depending on the Password Protected Sharing setting in the Network and Sharing Center window). Examples of Private networks are home and business networks managed by you or someone you trust.

For information about dealing with the Unknown Network problem, see “File and Printer Sharing Without a Router: Avoiding the Unidentified Network Problem,” p. 405.

Domain network—A network that is managed by one or more computers running a Windows Server OS. This is a trusted network, and the security of the network and its member computers is managed by network administrators.

The first time you connect to a given network, Windows should prompt you to select the appropriate network location. Windows can take up to a couple of minutes to prompt you after you’ve connected to a new network for the first time. For whatever reason, you can’t hurry the process along. During this time, it will treat the network as a public network, and file sharing will be disabled. Wait a minute or so for Windows to prompt you.

You can view the current setting through the Network and Sharing Center. On Domain networks, this location is not changeable, but it can be changed for the other types of networks.

If you need to change a network’s location type, click or touch the Network icon in the taskbar, select Network Settings, and then click or touch the name of the network you want to change. Scroll down to the bottom of the screen and select Advanced Options. To specify a safe, private network, turn on Find Devices and Content. To specify a public, unsafe network, turn off Find Devices and Content. Windows automatically changes several settings that affect the security of the computer when you connect to these various types of networks. On Domain networks, Group Policy configures the settings for network discovery and file and printer sharing alike. When you connect to a Public network, Windows disables network discovery and file and printer sharing.

After connecting, you can change these default settings, but you really should not enable file and printer sharing when you’re connected to a network that might contain computers that are unknown to you or are not under your control.

Wi-Fi Sense can connect you to three categories of Wi-Fi networks:

Open (passwordless, unsecured) networks to which other Windows users’ computers have successfully connected. When you connect to an unsecured network, Windows sends the network name and location to Microsoft, which can then pass this information along to other users via Wi-Fi Sense.

Networks run by organizations that have made arrangements with Microsoft to provide public access.

Secured networks intentionally shared by other Windows users who are your friends and contacts on Facebook, Skype, and Outlook (as of the time this was written, and perhaps more contact sources over time). Wi-Fi Sense sends your computer the networks’ setup information in encrypted form, so that you can use your contacts’ shared networks without having to know (or being able to see) their passwords.

Wi-Fi Sense works only if your device has Locations Services turned on, so it can tell where you are. Automatic connection to networks shared by contacts is available only if you are signed in using a Microsoft (online) account.

To learn more about this new feature, see “Wi-Fi Sense,” p. 25.

To enable Wi-Fi Sense, follow these steps:

1. Click or touch the network icon in the taskbar and select Network Settings.

2. At the left, select Wi-Fi if it’s not already selected. Then scroll down and select Manage Wi-Fi Settings.

3. To connect automatically to networks that Microsoft knows about, turn on the switch under Wi-Fi Sense (or more precisely, under Learn More).

4. To connect automatically to networks shared by friends and colleagues in your Contacts list, turn on the switch under Connect to Networks Shared by My Contacts. These people must also list you in their contacts lists, must be using Windows 10 or Windows Phone 8.1, and must have enabled sharing on individual networks in their Wi-Fi network list.

5. Click the Back button at the top left of the Settings window to display the main Settings screen. Select Privacy, Location. Above the Change button, if it says Location for This Device Is Off, select Change, then turn on Location for This Device. Further down is another switch labeled Location. Be sure it is set to On.

Now, your computer will be able to connect to public and shared Wi-Fi networks as you travel around.

To share networks you know about with your friends and contacts, see “Sharing Wi-Fi Network Settings with Friends,” p. 397.

The basic steps are the same in each case:

1. Click the network icon at the right end of the taskbar.

2. The Networks panel opens, as shown in Figure 36.1. Windows displays a list of the names (SSIDs) of the wireless networks that it “hears.”

Click or touch a network name. If you want to use this network whenever you’re in its range, check Connect Automatically. If you are connecting to the network only temporarily, and you’re in range of another network that you would normally prefer to use, uncheck Connect Automatically. Then select Connect.

3. Windows determines what type of security the network is using. If the network is encrypted, it prompts you to enter the network key. Enter the passphrase or the 10- or 26-digit hexadecimal key that was used when the network was set up. The network’s owner will have to tell you what this is.

(If you are signed in using a Microsoft [online] account, and you have previously connected to this wireless network using a different computer or device, you might not need to enter the password; the network information is part of your user profile and is synced from device to device, unless you disabled this in your account’s privacy settings.)

4. When the connection has been established, Windows should ask whether you want to “find PCs, devices and content on this network.” This is how you indicate whether you’re using a trusted private network or a potentially unsafe public network. It is very important that you make the right selection, so we discuss this setting in detail in the following sections.

Windows will save the password you enter, so the next time you return to this location, you can reconnect without having to reenter it. You can change other connections as described later in this chapter under “Managing Wireless Network Connections.”

The following sections tell you how to proceed to protect your privacy, depending on the type of network you’ve chosen: corporate, your home/small office, someone else’s home or office, or a public place.

Within a minute of connecting for the first time, Windows should ask you, “Do you want to find PCs, devices and content on this network, and automatically connect to devices like printers and TVs?” If the network is private, under your control, and you trust the other users and computers on the network, you can select Yes. This enables file and printer sharing over the network. If the network is a place where you can’t trust every other computer and user, select No. If in doubt, click No. You can always turn on sharing later.

Make the connection as described in the previous section, but be sure you’re not inadvertently making the contents of your computer available to other people on the network. Follow these precautionary steps:

1. When you make the connection, if you’re asked if you want your PC to be discoverable by other PCs and devices on the network, select No, and you’re finished.

2. If you aren’t prompted shortly after you make the connection, click or touch the Network icon in the taskbar, select Network Settings, click or touch the name of the network to which you’re connected, scroll down and click Advanced Options, and turn off Find Devices and Content.

Even with sharing turned off, you can still use network resources shared by others on the network. They just won’t be able to get into your computer.

If for some reason you do want to temporarily let someone there use files or printers shared by your computer, here’s the safest way to do it:

1. Click or touch the Network icon in the taskbar, select Network Settings, click the name of the network to which you’re connected, scroll down and click Advanced Options, and then turn on Find Devices and Content.

2. Create a user account just for the person who needs access to your computer (see Chapter 3) and create a password for it.

3. Right-click the network icon in the taskbar and click Open Network and Sharing Center. In the Network and Sharing Center, click Change Advanced Sharing Settings, scroll down, open the All Networks section, and select Turn On Password Protected Sharing, as shown in Figure 36.2. Click Save Changes.

4. Right-click a folder you want the other user to access, select Share With, and then click Specific People to open the File Sharing dialog box. Enter the account name, click Add, and then Share.

You can later remove the user account or change its password.

For information on creating a new user account, see “Setting Up User Accounts,” p. 73.

For additional information on sharing files safely, see Chapter 21, “Using a Windows Network.”

One path for attack at a public hot spot is through files that client computers accidentally share. When you connect, follow these steps:

1. When you make the connection, if you’re asked whether you want to find PCs, devices, and content on the network automatically, click No, and you’re set.

2. If you aren’t prompted about finding devices shortly after you connect, click or touch the Network icon in the taskbar, select Network Settings, click or touch the name of the network to which you’re connected, scroll down and click Advanced Options, and then turn off Find Devices and Content.

On open unsecured public hot spots, it’s possible for eavesdroppers to listen in on other people’s wireless traffic. Even if the network is secured with encryption, it’s possible for eavesdroppers to listen to traffic if they can break the encryption scheme. It can take them mere seconds to break WEP encryption, for example.

Therefore, at a public location, you should be very careful when you use websites that display sensitive information or that require you to enter a password. If the URL of the website starts with https:, your data will be protected. If the URL starts with just http:, think twice about signing in.

Computers, laptops, and tablets can also communicate with each other directly, without an access point or router. This is called an ad hoc wireless network. You might use an ad hoc network so that you can share files with another person in a meeting without requiring any additional hardware. Another common use for an ad hoc network is to let one computer share a direct Internet connection with other devices. For example, you may have a tablet or laptop that has a cellular data modem and want to share this Internet connection with another device. This is called tethering.

One computer needs to “create” the ad hoc network. Then users of various types of devices can join it just as they do any other wireless network, by choosing the network’s name from a list of available networks.

Windows 10 can join an existing ad hoc wireless network, but unfortunately Microsoft removed from Windows the capability to easily create one. There is, however, a way you might be able to create one manually, if your Wi-Fi adapter supports it. You can try these steps:

1. Open an elevated Command Prompt window by pressing Windows Logo+X, and then selecting Command Prompt (Admin) or Windows PowerShell (Admin), whichever appears in the pop-up menu. Confirm the User Account Control prompt.

2. Type the command netsh wlan show drivers and press Enter. Look for the line “Hosted Network Supported.” You might need to scroll up to see it. If that line says No, you’re out of luck; Windows can’t work with your wireless adapter’s driver to create an ad hoc network. If it says Yes, you can proceed.

3. Type these two commands:

Click here to view code image

netsh wlan set hostednetwork mode=allow ssid=networkname key=passkey keyUsage=persistent netsh wlan start hostednetwork

However, substitute the name you’d like to give your network for networkname and enter a passphrase of your own devising, using eight or more letters and numbers, for passkey. Press Enter after typing each line.

If you get the message “The group or resource is not in the correct state to perform the requested operation,” open the Network and Sharing center, select Change Adapter Settings, and be sure that the icon subtitled Microsoft Hosted Network Virtual Adapter is not disabled. If it is, right-click it and select Enable. Then try the netsh wlan start hostednetwork command again.

4. At the right end of the taskbar, right-click the network icon. Select Open Network and Sharing Center. Select Change Adapter Settings. You will see a new icon that corresponds to the ad hoc network you just created. Make note of its name. (It might be something like “Wireless 2.”)

5. In the Network and Sharing Center, locate the link after the word Connections: that corresponds to your Internet connection (for example, your Ethernet or cellular modem connection) and click it. Click Properties, select the Sharing tab, and check Allow Other Network Users to Connect Through This Computer’s Internet Connection. In the Home Networking drop-down list, select the ad hoc network device you noted in the preceding step. Click OK.

Other devices should now be able to see the network you created, and they’ll have Internet connectivity through your computer. This ad-hoc network will not restart itself if you shut down and restart Windows. You’ll have to re-enter the netsh wlan start hostednetwork command in an elevated Command Prompt window.

If you want to enable file and printer sharing on the ad hoc network, click or touch the Network icon in the taskbar, select Network Settings, click or touch the name of the ad hoc network you created, scroll down and click Advanced Options, and turn on Find Devices and Content.

To delete the ad hoc network, follow these steps:

1. If you shared your Internet connection with the ad-hoc network, stop sharing it by repeating the procedure in the preceding step 5, but uncheck Share This Connection.... Then click OK.

2. Press Windows Logo+X and select Command Prompt (Admin) or Windows PowerShell (Admin). Confirm the User Account Control prompt. Type netsh wlan stop hostednetwork and press Enter.

When Windows is not currently connected to any wireless network, it scans through its list of known networks, in order. If any are in range, and you have enabled automatic connection, Windows selects the one it thinks you’re most likely to want to use and then connects. (Windows versions 7 and earlier let you manually prioritize the list of known networks. Windows 10, 8, and 8.1 guess based on your past use, and let you change the networks if they guess wrong.)

In most cases, this system works without any adjustments, but there are ways to change the preferences if necessary, as we discuss in the next few sections.

If you are in an area where your computer can receive signals from two or more known networks—that is, networks to which you’ve previously connected—at the same time, you might want to tell Windows which one to use in preference to the others. One might have faster download speeds. Or you might want to connect to your neighbor’s network when yours is out of reach, but if both are available, you want to use yours.

How does Windows know which to use? In Windows 7 and earlier versions, you could sort the list of known networks into your own preferred order. Windows would use whatever available network was topmost in the list.

Windows 10 doesn’t let you manually sort the list of networks, but it does let you switch between available networks, and it keeps track of which network you end up actually using, if more than one is available. To train Windows, you must manually switch networks, using these steps:

1. View the list of available networks by clicking the network icon in the taskbar.

If you are currently connected to a network, it will be labeled Connected.

2. If you want to connect to a different network, click or touch its name and then select Connect.

Windows should remember your preference for this connection over the other one for future connections.

You can also give hints to Windows by changing a network’s connection properties. You can put each network into one of three priority categories. To set these categories, right-click the taskbar’s Network icon, and select Open Network and Sharing Center, Change Adapter Settings. Right-click the wireless adapter, and then select Status, Wireless Properties. Designate how you want Windows to treat the network. Here’s the list of options (see Figure 36.3):

This is a top-choice network. I’m happy to use this one anytime. Stick with this network until the signal is lost. Check Connect Automatically When This Network Is in Range, and uncheck Look for Other Wireless Networks While Connected to This Network.

This is a backup network. Use it if necessary, but if a top-choice network becomes available, switch over—check Connect Automatically, and then also check Look for Other Wireless Networks.

This is a special-purpose network or a last resort. Connect to it only when I tell you to—uncheck Connect Automatically.

This approach doesn’t really make them secure, just difficult for you to connect to. A network that does not broadcast its network name (SSID) usually will not appear in the list of available networks. (Although it might, if Windows overhears network traffic that includes the name.) To connect to such a hidden network, you must enter its connection information manually. Follow these steps:

1. Right-click the network icon at the right end of the taskbar; then click Open Network and Sharing Center.

2. Select Set Up a New Connection or Network, Manually Connect to a Wireless Network, and then click Next.

3. Enter the network’s name (SSID), set the security type, and enter the key, if required.

4. For a network that does not broadcast its SSID (a choice the network’s owner made in a futile attempt to hide his network from hackers), check Connect Even If the Network Is Not Broadcasting. This network will now always appear in the list of (potentially) available connections. You should not check Start This Connection Automatically. If you do, your computer will frequently broadcast the name of the network it’s looking for, advertising its name to hackers.

5. Click Next, and then click Close to save the new profile.

To later connect to a network with a hidden SSID when you’re in range, open the list of available networks, click the name of the network, and click Connect.

1. Click the network icon in the taskbar and select Network Settings. Select the Wi-Fi page at the left side if it’s not already; then scroll down and select Manage Wi-Fi Settings.

2. Under Manage Known Networks, click the icon for a connection that you no longer want and select Forget.