Disable Ad-Hoc Networking
As previously mentioned, we recommend for security reasons that you operate your wireless home network in infrastructure mode, meaning a wireless router provides the central point of the network and all wireless computers communicate only with the central point, not to each other directly (which is called ad hoc). This is a relatively low security risk, but there is a small possibility that those sitting next to us in an airport or other public location can try to make an ad-hoc connection directly between their laptop and ours.

Because we only ever plan to use our laptop computers connected to a wireless router in infrastructure mode, we should disable ad-hoc networking mode so that it is not possible for another laptop computer to attempt to make a connection directly to our laptop.

Using the Linksys NIC management utilities (such as WLAN Monitor), we do this by selecting infrastructure mode. When using Windows XP, the operating system manages most wireless NICs for us, and an additional step is required.

If your laptop or NIC does not support doing so, do not worry about it too much; if it is supported, however, why not take advantage of it? Here is how to disable ad-hoc wireless networking in Windows XP for a built-in wireless NIC:

1. Bring up the properties of the wireless NIC. Click the Wireless Networks tab (See Figure 25). In the Preferred Networks section, click the Advanced button.

Figure 25. Wireless Networks Tab
2. Select Access point (infrastructure) networks only (See Figure 26).

Figure 26. Do Not Allow Ad-Hoc Connections
3. Click Close.

Now, if we encounter another compute with a wireless NIC that attempts to set up an ad-hoc connection, our wireless NIC will not respond to the attempt, keeping our wireless network (and laptop) secure.

Next: Prevent unintentional Roaming and a Wireless Security Checklist

About the Authors
Jim Doherty is the director of marketing and programs with Symbol Technologies' industry solutions group. Before Symbol, Jim worked at Cisco Systems, where he led various marketing campaigns for IP telephony and routing switching solutions. Jim holds a B.S. degree in electrical engineering from N.C. State University and an M.B.A. from Duke University.

Neil Anderson is a senior manager in enterprise systems engineering at Cisco Systems and is currently responsible for large corporate customers in the areas of routing and switching, wireless, security, and IP communications. Neil holds a bachelor's degree in computer science.

To contact either author, please email: reviews@ciscopress.com and use Home Network Security Simplified/post question as the subject line.

Title: Home Network Security Simplified ISBN: 1-58720-163-1 Authors: Jim Doherty, Neil Anderson Chapter 2: Tip 2: Secure Your Wireless Network Published by Cisco Press

Reproduced from the book Home Network Security Simplified. Copyright [2006], Cisco Systems, Inc. Reproduced by permission of Pearson Education, Inc., 800 East 96th Street, Indianapolis, IN 46240. Written permission from Pearson Education, Inc. is required for all other uses.

*Visit Cisco Press for a detailed description and to learn how to purchase this title.

Another article by the same authors: Voice over IP--The Basics