A wireless network is very much like a cordless telephone. There is the router, which is analogous to a cordless phone's base unit; and a computer (often a laptop) equipped with a wireless network adapter, which is analogous to a cordless phone's handset. The two pieces communicate by two-way radio. Anyone with the proper radio equipment can listen in on the "conversation."
Cordless phones and wireless networks can interfere with one another. Wireless networks operate using the 2.4GHz frequency, the same as used by many corless phones. The symptoms of interference can be noise on the phone, or limited range of the phone handset or wireless computer. One solution is to replace the cordless phone with a newer model, one that uses the 5.8GHz frequency.
At home — Setting up your wireless router:
Change the router's password (the one used for getting to the router's configuration screens). Every good geek knows all of the default (out of the box) passwords for each make of router. Note that this password is different in purpose — and should be different in value — from the wireless passwords described below.
Change the router's SSID ("service set identifier"). This is the name that identifies your router to a potential wireless user. You want to make your LinkSys (for example) router easily distinguishable from your next-door neighbor's LinkSys router, both of which would have the same default (out of the box) SSID. Keep it simple but somewhat unique (it's not meant to be secret like a password) — try using your name or street address (e.g.: "5132elmwood").
Enable wireless security. This will scramble (encrypt) the communication between the router and the wireless computer, and make it more difficult for someone to listen in. It will also help keep outsiders from using your wireless connection without your permission (you could be held responsible for anything illegal or embarrassing they might do).
Most wireless routers can support some form of WEP (wired equivalent privacy). WEP is very weak protection, but better than nothing. WEP is also unhandy because it uses passwords that often must be typed in cumbersome hexadecimal notation.
WPA (Wi-Fi protected access) is much more secure and should be used if possible (unfortunately, many older routers and wireless computers do not support it). WPA allows the use of passwords that are more human friendly than hexadecimal numbers. WPA is more secure because it uses "temporal keys" — random passwords that change over time, making them very difficult to "crack."
On the road — Using laptop computers:
Be aware that most wireless "hot spots" (in coffee shops, hotels, airports, etc.) are so-called "open" networks. Your computer is more exposed than when you are at home (see above). For example, if there is a virus on a computer at a coffee table nearby, the virus may be burrowing into your system, stealing your data, and using your computer to send out spam.
Avoid doing confidential or financial transactions while using an open wireless network, even if you think you are connecting to a "secure" web site. Someone nearby may be using a "sniffer" and recording everything you do (perhaps without their knowledge).
Laptop computers are notorious for "growing legs" (they are easily stolen). Don't leave it unattended in a public area, even for a moment. Put a password on your computer that you must enter each time you turn it on, or log in; make your screen saver require a password. Don't store sesitive personal information — credit card numbers, Social Security numbers, bank access codes and passwords — on a laptop computer.