Deploying Secure 802.11 Wireless Networks with Microsoft Windows

Setting Up a Wireless Network Without a Wireless Access Point

This section describes how to set up a wireless network for a home or small business when you are not using a wireless AP (ad hoc mode). For an ad hoc wireless network, you must set up an initial wireless client that assumes some of the responsibilities of a wireless AP with respect to beaconing the name of the ad hoc wireless network to other wireless network clients.

To secure your ad hoc mode home or small business wireless network, you must use open system authentication and WEP encryption.

NOTE WPA does not support ad hoc wireless networks.

Configuring the Initial Wireless Client

The configuration of the initial wireless client depends on the following factors:

• Whether the wireless network adapter driver supports the WZC service.

• Whether you are using Windows XP (prior to SP1) or Windows XP (SP1 and later).

Wireless Network Adapter Driver Supports the WZC Service with Windows XP (Prior to SP1)

Use the following procedure to configure the initial Windows XP (prior to SP1) wireless client for your ad hoc mode wireless network when the wireless network adapter supports the WZC service:

1. Install your wireless network adapter in Windows XP. This process includes installing the proper drivers for your wireless network adapter so it appears as a wireless connection in Network Connections.

2. Because there might not be any wireless networks in your home or small business location, you might not be prompted with a message in the notification area of your taskbar. If you are notified, click the notification. You should see a Connect To Wireless Network dialog box. Click Advanced.

3. If you are not notified, right-click the wireless network adapter in Network Connections and then click Properties.

4. On the Wireless Networks tab of the wireless network adapter properties dialog box, click Add under Preferred Networks.

5. In the Wireless Network Properties dialog box, type the name of your ad hoc wireless network in Network Name (SSID).

6. Select the Data Encryption (WEP Enabled) and This Is A Computer-To-Computer (Ad Hoc) Network check boxes. Clear the The Key Is Provided For Me Automatically check box.

7. In Key Format, select a key format.

8. In Key Length, select a key size.

9. In Network Key, type the WEP key.

10. In Key Index, select 0.

11. Click OK to save changes to the wireless network.

12. Click OK to save changes to the wireless network adapter.

Figure 12-6 shows an example of a Wireless Network Properties dialog box for a home ad hoc wireless network with the following configuration:

• SSID is HOME-AD HOC.

• WEP is enabled.

• Open system authentication is enabled.

• Ad hoc mode is enabled.

• The WEP encryption key is 104 bits long, is in hexadecimal format, uses key index 0 (the first encryption key position), and consists of the sequence 19a8bce753ed4e6a410b730fa4.

Figure 12-6. Example of Windows XP (prior to SP1) configuration for an ad hoc mode wireless network.

Wireless Network Adapter Driver Supports the WZC Service with Windows XP (SP1 and Later)

Use the following procedure to configure the initial Windows XP (SP1 and later) or Windows Server 2003 wireless client for your ad hoc mode wireless network when the wireless network adapter supports the WZC service:

1. Install your wireless network adapter in Windows XP or Windows Server 2003. This process includes installing the proper drivers for your wireless network adapter so it appears as a wireless connection in Network Connections.

2. Because there might not be any wireless networks in your home or small business location, you might not be prompted with a message in the notification area of your taskbar. If you are notified, click the notification. You should see a Wireless Network Connection dialog box. Click Advanced.

3. If you are not notified, right-click the wireless network adapter in Network Connections and then click Properties.

4. On the Wireless Networks tab in the wireless network adapter properties dialog box, click Add under Preferred Networks.

5. On the Association tab in the Wireless Network Properties dialog box, type the name of your ad hoc wireless network in Network Name (SSID).

6. Select the Data Encryption (WEP Enabled) and This Is A Computer-To-Computer (Ad Hoc) Network check boxes. Clear the The Key Is Provided For Me Automatically check box.

7. In Network Key and Confirm Network Key, type the WEP key.

8. In Key Index, select 1.

9. Click OK to save changes to the wireless network.

10. Click OK to save changes to the wireless network adapter.

Figure 12-7 shows an example of a Wireless Network Properties dialog box for a home ad hoc wireless network with the following configuration:

• SSID is HOME-AD HOC.

• Open system authentication is enabled.

• WEP is enabled.

• Ad hoc mode is enabled.

• The WEP encryption key is 104 bits long, is in hexadecimal format, uses key index 1 (the first encryption key position), and consists of the sequence 19a8bce753ed4e6a410b730fa4.

Figure 12-7. Example of Windows XP (SP1 and later) configuration for an ad hoc mode wireless network.

Wireless Network Adapter Driver Does Not Support the WZC Service

When the initial Windows wireless client does not support the WZC service, use the configuration software provided by the network adapter vendor to configure the following:

• SSID of your ad hoc wireless network.

• Ad hoc wireless network mode (enabled).

• Open system authentication (enabled).

• WEP encryption (enabled).

• WEP key size.

  For the best security, select 104-bit WEP keys.

• WEP key format.

  For the best security, select hexadecimal format.

• WEP encryption key memory position.

  For the easiest configuration, select the first encryption key memory position.

• WEP encryption key.

Configuring the Additional Windows XP Wireless Clients

The configuration of additional wireless clients depends on the following factors:

• Whether the wireless network adapter driver supports the WZC service.

• Whether you are using Windows XP (prior to SP1) or Windows XP (SP1 and later).

Wireless Network Adapter Driver Supports the WZC Service with Windows XP (Prior to SP1)

Use the following procedure to configure additional Windows XP (prior to SP1) wireless clients for your ad hoc mode wireless network when the wireless network adapter supports the WZC service:

1. Install your wireless network adapter in Windows XP. This process includes installing the proper drivers for your wireless network adapter so it appears as a wireless connection in Network Connections.

2. When the computer is within range of the initial wireless client in your home or small business, Windows XP should detect it and prompt you with a message in the notification area of your taskbar.

3. Click the notification message. If you are not notified, right-click the wireless network adapter in Network Connections and click View Available Wireless Networks.

   In either case, you should see a Connect To Wireless Network dialog box.

4. Click Advanced.

5. In the wireless network adapter properties dialog box, click your wireless network name and click Configure.

6. In the Wireless Network Properties dialog box, select the Data Encryption (WEP Enabled) check box and clear the The Key Is Provided For Me Automatically check box.

7. In Key Format, select the encryption key format as configured on the initial wireless client.

8. In Key Length, select the key size as configured on the initial wireless client.

9. In Network Key, type the key as configured on the initial wireless client.

10. In Key Index, select the index corresponding to the encryption key memory position on the initial wireless client.

11. Click OK to save changes to the wireless network.

12. Click OK to save changes to the wireless network adapter.

Wireless Network Adapter Driver Supports the WZC Service with Windows XP (SP1 and Later)

Use the following procedure to configure additional Windows XP (SP1 and later) wireless clients for your ad hoc mode wireless network when the wireless network adapter supports the WZC service:

1. Install your wireless network adapter in Windows XP. This process includes installing the proper drivers for your wireless network adapter so it appears as a wireless connection in Network Connections.

2. When the computer is within range of the initial wireless client in your home or small business, Windows XP should detect it and prompt you with a message in the notification area of your taskbar.

3. Click the notification message. If you are not notified, right-click the wireless network adapter in Network Connections and click View Available Wireless Networks.

   In either case, you should see a Wireless Network Connection dialog box.

4. Click Advanced.

5. In the wireless network adapter properties dialog box, click your wireless network name and click Configure.

6. On the Association tab, select the Data Encryption (WEP Enabled) check box and clear the The Key Is Provided For Me Automatically check box.

7. In Network Key and Confirm Network Key, type the WEP key as configured on the initial wireless client.

8. In Key Index, select the index corresponding to the encryption key memory position configured on the initial wireless client. For example, if the initial wireless client is running Windows XP (prior to SP1) and is using key index 0, set the key index to 1. If the initial wireless client is running Windows XP (SP1 and later) or Windows Server 2003 and is using key index 1, set the key index to 1.

9. Click OK to save changes to the wireless network.

10. Click OK to save changes to the wireless network adapter.

Wireless Network Adapter Driver Does Not Support the WZC Service

When additional Windows wireless clients do not support the WZC service, use the configuration software provided by the network adapter vendor to configure the following:

• SSID of your ad hoc wireless network.

  The SSID must be the same as configured on the initial wireless client.

• Ad hoc wireless network mode (enabled).

• Open system authentication (enabled).

• Enable WEP encryption (enabled).

• WEP key size.

  Select the key size as configured on the initial wireless client. If the wireless network adapter does not support the same encryption key length as the initial wireless client, you must reconfigure the initial wireless client. For example, if the initial wireless client supports 40-bit and 104-bit WEP key sizes, and your wireless network adapter supports only 40-bit keys, you must reconfigure the initial wireless client to use a 40-bit WEP key.

• WEP key format.

  Select the same WEP key format as configured on the initial wireless client. If the wireless network adapter does not support the same encryption key formats as the initial wireless client, you must reconfigure the initial wireless client. For example, if the initial wireless client supports keyboard and hexadecimal WEP key formats, and your wireless network adapter supports only keyboard format, you must reconfigure the initial wireless client to use keyboard format for the WEP encryption key.

• WEP key.

  Type the same encryption key as configured on the initial wireless client.

• WEP encryption key memory position.

  Select the same WEP encryption key memory position (or encryption key number) as configured on the initial wireless client.