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Computerworld - Bad guys don't target just big, corporate networks. If you have a Wi-Fi network at home or in a small office, intruders may be after you, such as casual "war drivers" who troll city streets, looking for unprotected wireless networks. (Want to know more? See "Why you need wireless protection.")

It may not just be malicious attackers who cause problems. If you don't change the defaults of your wireless network, a neighbor with the same router make and model might accidentally connect to your network, stealing your bandwidth or reconfiguring your router and network without your knowledge.

Fear not, though. There's plenty you can do to protect yourself. In this article, I'll show you how.

Change your administrator password

Before you do anything else, change the administrator password on your router. Every model of router comes preconfigured with a standard password, and hackers know this. So it's exceedingly easy for someone to hop onto your network, gain full control over its administrative rights and wreak havoc.

How you change your password varies from router to router, so I'll show the steps for a representative model: the Linksys WRT54GX4.

Sound off on wireless security Why you need wireless protection Preston Gralla gives five good reasons you should take wireless security seriously. Why worry about wireless? Wireless security threats are overhyped and easily stopped, says David Ramel. How to protect your wireless network Gralla provides step-by-step instructions for keeping your network safe.

1. Log in to the setup screen by opening your browser and going to http://192.168.1.1. When the login screen appears, leave the username blank. In the password section type admin, and then press Enter.

2. Click the Administration link, then click Management. At the top of the page, you'll see the Router Password area. Type a password into the Router Password box, then retype it in the "Re-enter to confirm" box. From now on, when you log in, use that password instead of admin when you log in to your router.

Changing your router's password. (Click image to see larger view)

Stop broadcasting your network's SSID -- and change its name

Your service set identifier (SSID) is your network's name, and if people know what your SSID is, it's easier for them to find your network and connect to it. Your router broadcasts its SSID, and that broadcast tells passersby there's a network there. It also gives out the name.

So, if you turn off SSID broadcasting, you'll go partway toward keeping casual users from seeing your network. But doing that, by itself, won't necessarily solve the problem. Even if you stop broadcasting your network's name, people might still be able to connect to your network. That's because manufacturers generally ship their wireless routers with the same generic SSID; for example, Linksys routers all have the SSID Linksys by default. So, even if you stop broadcasting your SSID, intruders can easily guess your router's name and log on.

Changing your SSID name from the default. (Click image to see larger view)

To solve the problem, first change your SSID's name, and then hide it. That way, passersby won't see it, and they won't be able to guess it either. How you do this varies from manufacturer to manufacturer, and even from model to model from the same manufacturer. But for many models of Linksys routers, including the WRT54GX4, here's what to do.

1. Log in to the setup screen, then click the Wireless tab and look for the Wireless Network Name (SSID) box. Enter the new name of your network.

2. On the same screen, look for the Wireless SSID Broadcast setting, and choose Disable. Then, click Save Settings.

3. If you are doing this from a wireless PC, you will immediately lose your connection to your network. So will every other wireless PC on your network. After you change your network name, reconnect each Wi-Fi computer to the network, using the new network name. You're now set.