The more precautions you take, the better off you'll be.
There are a number of steps that even non-technical users can take to make a wireless network more secure. Some general instructions follow, but you will need to refer to the owner’s manual for your wireless equipment for more specific instructions.
Use personal firewalls. One of the easiest ways to guard a network from attack is to set up a personal firewall. Top firewall software products include ZoneAlarm Pro (free to download at http://www.zonelabs.com/), Norton Personal Firewall and McAfee Personal Firewall Plus. If you are running Windows XP, Microsoft’s built-in firewall may already be turned on. Check also with your computer manufacturer to learn if firewall software has already been installed and enabled on your machine.
Change your name. Most systems use a default SSID (network name) such as “wireless” or “default.” Hackers know that the popular LINKSYS product uses the name “linksys” as its SSID. Be sure to change default names to something unique that will not attract unwanted attention.
Disable SSID broadcasting. Doing this hides the presence of your wireless network or at least obscures the SSID itself which is critical for a device to connect to your network. By turning off the broadcast SSID function, a hacker will have to guess your network’s name to get in.
Scramble your data. In order to protect your data from prying eyes, you should scramble or “encrypt” it so that nobody else can read it. Most recent wireless equipment comes with both WEP (wired equivalent privacy) and WPA (Wi-Fi protected access) encryption tools that you can enable. WPA is more robust and should be used if supported by your equipment.
Block casual intruders. Each network device has a unique identifier called a Media Access Control (MAC) address, similar to a serial number. Some wireless devices allow users to create an “authorize MAC address table” which means only devices with serial numbers you’ve approved are allowed on the network.
Remember that even with all these steps, there’s no way to guarantee 100 percent security for a wireless network. Since protecting your wireless network is all about improving the odds that you’ll be safe, the more steps you decide to take the better off you’ll be.