Not all wireless devices support ad hoc networking, but most seem to. To determine whether your PC supports ad hoc networks, open a command prompt with administrative privileges, which you can do by selecting Command Prompt (Admin) from the WinX menu, and then run the command netsh wlan show drivers. If the Hosted Network Supported line shows Yes, then your PC supports creating an ad hoc network. The following shows the output.

C:>netsh wlan show drivers

Interface name: Wi-Fi
    Driver                    : Intel(R) Centrino(R) Advanced-N 6230
    Vendor                    : Intel Corporation
    Provider                  : Microsoft
    Date                      : 10/7/2011
    Version                   : 14.2.1.3
    INF file                  : C:WINDOWSINF
etwns64.inf
    Files                     : 2 total
                                C:WINDOWSsystem32DRIVERSNETwNs64.sys
                                C:WINDOWSsystem32driversvwifibus.sys
    Type                      : Native Wi-Fi Driver
    Radio types supported     : 802.11a 802.11b 802.11g
    FIPS 140-2 mode supported : Yes
    802.11w Management Frame Protection supported : No
    Hosted network supported  : Yes

Windows 7 provided graphical tools to create ad hoc networks. However, with Windows 8.1, you need to run commands at a command prompt with administrative privileges. Open the command prompt and run these commands, replacing <name> and <password>:

netsh wlan set hostednetwork mode=allow ssid=<name> key=<password>

netsh wlan start hostednetwork

For example, you might run the following command:

C:>netsh wlan set hostednetwork mode=allow ssid=QuickNet key=mG9s5Unx
The hosted network mode has been set to allow.
The SSID of the hosted network has been successfully changed.
The user key passphrase of the hosted network has been successfully changed.

C:>netsh wlan start hostednetwork
The hosted network started.

As shown in Figure 22-1, the new (QuickNet) network appears in the Network And Sharing Center.

Figure 22-1. Use ad hoc networking to turn your PC into a wireless access point.

Now you’ll be able to connect to the network from other wireless devices using the SSID and password that you specified, just as if it were a wireless access point. Once connected, you should be able to connect to other Windows PCs by name and by using homegroups.

When you no longer need the network, run the following command at the administrative command prompt to stop it: netsh wlan stop hostednetwork.

You can also use an ad hoc network to share an Internet connection. This is useful when you’re at a hotel that only supports a single Internet connection per room, but you have up to 20 devices that need to share the connection.

I know it might sound silly that you’d travel with multiple wireless devices, but for me, I typically travel with a mobile PC and a smartphone that supports wireless, and then each person in my family has a wireless device that they want to use to access the Internet. Particularly when in foreign countries/regions, I can save quite a bit in data roaming fees if I set up my own ad hoc wireless network in the hotel room to share the hotel’s Internet connection instead of having each person’s smartphone connect to the Internet via a mobile data provider.

First, connect one computer to the Internet with a wired or wireless connection. You can use a single wireless adapter to both connect to the Internet and create an ad hoc network to share the connection. Then, follow the instructions in the section Creating an ad hoc wireless network. Finally, share the Internet connection by following these steps:

You can now connect other wireless devices to your ad hoc network and access the Internet. If any wireless devices were previously connected to your ad hoc wireless network, disconnect them and then reconnect them.

This process turns your PC into a Network Address Translation (NAT) server and DHCP server, as described in Chapter 21. In many cases, even the PC’s wired Internet adapter will have a private IP address. That’s okay; you can have NAT within NAT.

If you’re curious about the inner workings of Internet Connection Sharing (ICS), run ipconfig /all at a command prompt on the PC sharing the Internet connection and then on the clients. You’ll find that the PC sharing the Internet connection has separate IP addresses for the Internet and private links. The private link will always be 192.168.137.1. Any computers connecting to the Internet will have an IP address in the range 192.168.137.127 to 192.168.137.255 and will have 192.168.137.1 as their default gateway and DNS server.

You might want to change these IP addresses if you are replacing an existing router and don’t want to renumber the clients. You can change these IP addresses by modifying several registry entries on the Windows 8.1 PC that will be sharing the connection. Modifying registry entries isn’t common in Windows 8.1; most settings are now defined using Group Policy. However, if you’re an old-school Windows user like I am, you probably already know the registry well, and you probably hate it, too.

To modify a registry entry, launch the Registry Editor. From the Start screen, type regedit and then press Enter. Next, browse to HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesSharedAccessParameters, as shown in Figure 22-4.

Figure 22-4. Use the Registry Editor to change the IP address that ICS uses.

To change the IP address ICS uses, modify the following values by double-clicking them:

Windows 8.1 automatically figures out the IP addresses to assign to clients and the subnet mask based on the IP address you choose. In other words, if you set the ScopeAddress to 10.1.1.1, ICS will assign clients addresses on the 10.1.1.0 network with a subnet mask of 255.255.255.0. ICS always uses a subnet mask of 255.255.255.0.

The previous sections described how to share an Internet connection using nothing but a wireless PC running Windows 8.1. The steps are rather complicated, though: you need to open an administrative command prompt, type a bunch of commands (which won’t be easy on a tablet), modify adapter properties to share a connection, and finally connect to the wireless network.

There are a couple of easier ways. Still using only Windows 8.1, you can run the Connectify Hotspot desktop app, available at http://www.connectify.me/. As shown in Figure 22-5, the free version works great. When prompted, be sure to allow Connectify Hotspot to communicate through Windows Firewall. After installation, you can start Connectify Hotspot from the Start screen and manage it from the desktop.

You can also bring a router with you. You could simply unplug your home router and bring it with you when you travel, though it might take up more room in your suitcase than you’re willing to sacrifice. As an alternative, you can buy a travel router for US$12–$50. Either way, just plug your router into your hotel’s Internet connection and then connect your devices to your router to share the connection.

Figure 22-5. Use Connectify Hotspot to simplify sharing an Internet connection.

To add a Bluetooth accessory, first put the accessory in discoverable mode. Check the accessory’s manual for specific instructions, but typically there’s a button you need to press. Sometimes, you need to press and hold the button. On smartphones, you should find the Bluetooth section of the settings.

On your PC, select PC & Devices from PC Settings, select Devices, and then select Add A Device. As shown in Figure 22-6, Windows will display any nearby Bluetooth devices that are in discoverable mode. Select a device to connect to it.

Figure 22-6. Put Bluetooth devices in discoverable mode before pairing.

Next, Windows 8.1 might ask you to perform some sort of authentication. This might involve typing a code into a keyboard or, as shown in Figure 22-7, confirming that two codes match. This authentication process helps prevent a sneaky person within a few feet of you from intercepting your connection.

You don’t need to remove a Bluetooth device when you’re done with it. Simply leave it configured, and it’ll be available the next time you want to use it. If you do want to remove a Bluetooth pairing, select PC & Devices from PC Settings, select Devices, select the device, and then select the – symbol in the upper-right corner.

Figure 22-7. Windows 8.1 often needs to authenticate Bluetooth pairings.

You can use Bluetooth to send files between two PCs. This is a clumsy and slow process (a maximum of 721 Kbps), but it’s an effective way to send a file or two when other forms of networking aren’t available and you don’t have a USB flash drive to exchange files.

The process involves five high-level steps:

If you need to send multiple files, compress them into a ZIP archive before transferring them. You can use the same process for transferring files to other devices, including smartphones. You might need to run a special app to transfer files to your smartphone, however.