You've just bought a wireless router so you can use your laptop all over the house. You get it all setup and surprise, surprise it works. Now that should be the end of it right? Wrong. The default setup for wireless networks is setup to get the network up and running but does nothing to protect your network.
The default setup will let anybody with a wireless network card with in range to connect to your network. If your isp charges you for going over your monthly download limit on your internet access and some one is using your internet access to download tons of stuff, you will get stuck with the bill! Not to mention they could access your files on your computer.
What can be done to protect your network? Well the following steps should help you secure your network. Remember there's no such thing as a totally secure network but we're gonna try and make it as damn hard as it can be to get into. :)
Password Protect Your Routers configuration page:
Most wireless routers use an internet browser to access and configure the settings. Make sure you password protect this so no one can change your settings. If it has a default login and password change it.
Use WEP Encryption:
Now WEP encryption isn't completely safe, in fact it can be hacked. But it will be one more thing to get past before getting into your network.
WEP uses an encryption key that the router and all wireless cards in your network will use to get access to each other. Key sizes are usually 64 bit or 128bit, though Dlink does have some with 256 bits. Use the highest encryption rate you got.
Also make it a habit of changing your WEP key ever week or so.
Turn off SSID Broadcasting/Beaconing:
By default your router will be broadcasting the name of your network. Turn this off. Every computer in your network must be set with your matching SSID.
Every network device is assigned its own alphanumeric serial code called a MAC address. Your routers config page should be able to tell you what your Wireless cards MAC address is.
Jot down the address or addresses if you have more than one wireless connection. In your routers configuration enable MAC filtering and add the wireless card(s) MAC address(es) to the list of MAC addresses the router will accept.
If your router encounters a MAC address that's not on the list it won't get through.
Limit the amount of possible connections to your network:
by default your router will assign each connection using DHCP (Dynamic Host Configuration Protocol) an ip address. It will also have a range of ip numbers to assign from. This could be setup by default to allow 100 or so connections to connect. It will have a starting ip address and an ending ip address. Narrow the range down to as many computers and laptops that you have in your network.
Lower your Broadcast Strength:
Some routers allow you to change the "performance" or the signal strength of your antenna's transmit power. Experiment by lowering your power, while still getting a fairly strong signal strength around 90% +. Try out everywhere you would normally use your laptop, outside, etc.
By reducing the signal strength there will be less chance of your neighbors getting a strong enough signal to connect to your network.