Believe it or not, there are people out there driving around LOOKING for networks from which they can steal personal data. What follows are some basic guidelines to help you keep your network safe from unauthorized access.
Keep software up to date!
More specifically, keep the firmware that is embedded (installed) in your hardware current! Software is never perfect or impenetrable when first released! Vulnerabilities are discovered and so patches are released by the manufacture to plug these security holes.
Even if you've just purchased a piece of network hardware, be sure to go to the manufacturers site immediately and check for updates! Do not assume what’s loaded onto your hardware is the most recent version! Security holes can allow someone access to your Internet connection and valuable data on your network computers!
Change the Administrator password!
The wireless router will come to you with a default password. This password should be changed immediately! Most... if not all... wireless routers leave the manufacturer with the Admin login name and password. I kid you not!
Go to the router’s configuration page and look for the link or title that says Admin. From there, you should be able to change the login name and password. If you have any trouble, just check the manual.
Change your SSID.
SSID or Service Set Identifier is the name of a wireless local area network. SSID is like a "secret" key that should be set by the network administrator. Every wireless router comes with a default SSID. However, all wireless devices on a network have the same SSID in order to communicate with each other. By changing it to a non-default SSID, you're making it harder for unauthorized connections to your network.
Turn off SSID Broadcasting.
The SSID broadcasts a signal (802.11 (Wi-Fi)) which allows each wireless network device to speak to one another. But allowing your SSID to broadcast makes it easier for rogue devices to be added to your network.
Once you've configured each of your wireless devices to the exact SSID you specify, turn broadcasting off!
Enable WEP
WEP or Wired Equivalent Privacy, encrypts the data moving to and from your wireless clients. When possible, you should use the strongest key possible, 128-bit.
Limit access by MAC addresses
Every network card (both wired and wireless) has a unique MAC (Media Access Control) address assigned by the manufacturer. Set your wireless router to allow connections from only specific MAC addresses and you'll greatly improve the security of your network. Here's how to find your MAC address... *
Windows NT/2000/XP - Click the Start button --> click Run --> type cmd and click OK.
- At the command line or C: prompt type ipconfig /all --> click Enter Your MAC address will be displayed as the Physical Address.
Windows 95/98/98SE/ME - Click the Start button --> click Run --> type winipcfg and click OK.
- Choose your network card from the drop down list.
- Your MAC address can be found in the Adapter Address field.
Once you've determined the MAC address for each of the network cards you're using, go to the manufacturer's site for your wireless router. There you'll want to find information on using MAC address security.
*Vista MAC info coming! 
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