By default, a wireless network is wide open to anyone in range with the proper equipment. If you have set up your router to distribute IP addresses via DHCP, it will cheerfully give them to anyone who walks by with a wireless enabled pocket pc or laptop. Even if you have not, all that is necessary is for them to figure out which IP address range you are using, or use an easily available wireless network detection program such as NetStumbler , and they are in your network. Hmmm.
All recent wireless routers/access-points come with two basic methods of securing their networks, WEP and MAC address filtering. A MAC address (also known as a physical address) is a unique hardware identifier assigned to every network device that looks something like '00-EF-78-C6-34-56'.
MAC address filtering involves manually entering a list of the addresses found in your local network (you can easily find the MAC addresses of your network adaptors by going to the command prompt and typing 'ipconfig /all') and configuring the router to allow only these specific addresses to connect via the wireless network.
The screenshot click here is an example of setting up MAC address filtering, in this case on a SMC Barricade 4port wireless router. Note that this router offers two separate modes for MAC address filtering, connection and association. Allowing association for a specific address allows that address to communicate with other wireless clients on the network, but not the wired network on the other side of the router or the Internet. Allowing connection enables a client full communication through the router.
MAC address filtering is a good basic method of securing your wireless network. Its drawbacks are that it requires some initial manual configuration, to obtain and enter the MAC addresses, and it can be defeated by using a network traffic capture program in conjunction with a wireless card, and reading an 'allowed' MAC address from a captured packet, then using this address on a new network adaptor.
Not that anyone would bother to do this to get into your home network, but business networks would be prime targets for this kind of exploit.
WEP or Wireless Encryption Protocol works by establishing a shared key between the clients and the access-point, then using the key to encrypt and de-encrypt the data passing between them. This offers adequate security for a home network, where the primary concern is that your neighbors do not find out what you are downloading.
To configure WEP, you must enable it on the router and on each wireless adaptor (use the management software that came with the card.), and designate a passphrase or key for the network, which must be entered identically on each system.
By now, hopefully, you have a secured wireless network running in your home, or are prepared to install one. We hope you have found this article easy to understand and use.