WiFi

WiFi is a family of related wireless technologies including 802.11a, 802.11b, 802.11g, and 802.11n. This list is also a timeline and a measure of speed. In general, avoid a & b, and choose n over g.

For years, I've used Linksys WiFi routers. I'm a big fan of what I call "warthogs" as in WaRThog: the WRT54GS, WRTGL, etc. I've played with alternate software but nowadays I'm running a WRT54GL straight outta the box. At some point I may try DD-WRT or OpenWrt.

If you're going to play with WiFi you need Network Stumbler. If nothing else use Net Stumbler to determine which channels *aren't* being used in your neighborhood. Then figure out which of your neighbors is too boneheaded to encrypt their WiFi signal.

WiFi is radio. It's broadcast indiscriminately to anyone within range. Your job is to lock down your network. There are two things you need to do: encrypt your traffic and contain the spread of your radio waves.

WPA is better than WEP and both are better than nothing. Encrypt your WiFi signal. It's a sin and a shame that manufacturers continue to ship access points with encryption turned off. Bozos...

A lock is only as good as its key. Your password needs to be strong as in hard to guess. The longer the password the more possible combinations have to be tried in order to guess it. The longer the key length the harder the brute force effort necessary. Practice good password hygiene when configuring your accces point's password.

Change the default password used to log in to your WiFi router or access point. This prevents me from sitting outside your house, logging in, and doing mischief.

The antennas that ship with consumer WiFi access points are omnidirectional. They propogate a signal equally in all directions. Put it in the center of your house or office and everyone will be able to connect to it relative to their distance away from the signal. The signal strength obeys the inverse square law so twice the distance is 1/4 the signal strength and 3 times the distance is only 1/9, 4X 1/16, etc. Use this to your advantage when setting up your WiFi router. If you're worried about someone parking next to your building, place the access point in the center of the building or on the far side.

You can further direct the radio waves buy either buying a directional antenna and point the radio signal where you want it (and away from where you don't want it) or use a reflector on your omnidirectional antenna. The former costs money and the latter is DIY homemade and free! There are two cardboard templates that can be assembled using aluminum foil and tape. The results are dramatic! Again, not only will a WiFi antenna reflector increase the signal strength when aimed properly it can also limit the signal to would-be eavesdroppers. Not that Eve won't resort to larger and larger antennas.

This parabolic antenna reflector is another story altogether. Good math, clean lines, and does the job nicely. I've made several of these over the years. Thick card stock, open your printer's back door to make a straight path, thick foil, and a glue stick. Explanation here. The elegant way is to spring for a Tritium Flatenna at 16 bucks.

Nothing beats wandering around your home or office running Net Stumbler listening to your own access point. How far away can you hear it? Are there blind spots? Are there places the signal pops up strong, further away than you'd imagined? When you want to literally map out your findings try Ekahau HeatMapper. As Jack used to say, "Measure and test. Measure and test..."

Here's a list of WiFi antenna hacks. Instructables if full of WiFi antenna mods. Take your pick.