I recently bought a Linksys WAP54G wireless access point and a wireless network card for my laptop, to allow me to use my laptop around the house.

A wireless access point allows you to add wireless connections to your existing wired network. It differs from a wireless router, which you'd typically use if your whole network was wireless (e.g. positioned between your computers and the broadband modem) and which usually includes firewall software.

My network consists of 5 computers:

• an old PC that serves as a gateway firewall
• another old PC, running Fedora Core 3, which is actually on its own "DMZ" network and acts as a web server (hosting this web site)
• my main desktop PC, running XP
• another desktop PC, also running XP
• my laptop, running Windows 2000

The wireless access point simply allows me to replace a length of Ethernet cable with the WAP at one end and the wireless network card at the other.

The Linksys WAP54G is a 802.11g machine that allows data transfer rates of up to 54Mbps. It comes with a CD and a configuration utility that makes setup a cinch. You can be up and using it in no time at all - and I was. The trouble is that the default setup has no security. It's completely wide open, so anyone in the vicinity can connect to your network. Linksys obviously wanted to make getting started as easy as possible, but turning on the security features of the WAP54G are less obvious.

If you read the User Guide you find out that you can configure the WAP54G via its web interface, by browsing to 192.168.1.245. However, when I tried this I could get a web page. The problem is that if your network is not in the 192.168.1.x range, you won't be able to access the web interface. This is the bit they don't tell you.

The solution is to temporarily take your computer (in my case my laptop) off the network, change its IP address to something in the 192.168.1.x range and connect it directly to the WAP54G using a network cable.

Doing this involved the following:

1. Taking out the new wireless network card and replacing it with the old Ethernet card.
2. Changing the IP address of the laptop from a dynamically assigned address to a static address in the 192.168.1.x range (see below for details of how to do this in Windows 2000 and XP).
3. Connecting the laptop to the wireless access point. Note: with the WAP54G you can use a normal patch cable, you don't need to use a crossover cable as you normally do for connecting computers peer-to-peer (see below).

Once I'd connected directly to the wireless access point using a computer with an IP address in the correct range (I chose 192.168.1.246) I could browse to http://192.168.1.245, log in using no user name and the password "admin" and then go through the process of turning off SSID broadcast, changing the password, changing the channel number and enabling encryption.

Note: Each time you apply a change the WAP becomes temporily unavailable, the browser will be unable to find the web page and your PC/laptop will tell you that the network cable has been unplugged. However, the connection will be reestablished after a few seconds. If you refresh the browser, the web interface will reappear.

In my case I wanted to change the IP address of the wireless access point, so that I could access it from computers with IP addresses in the address range of my network. If you need to do this, you should only change the IP address and gateway address of the wireless access point as the last thing you do, as you won't be able to reconnect from the computer in the 192.168.1.x range once you've done this. You'll have to change the IP address of your PC/laptop before you can access the configuration page again.

If, while configuring the WAP you managed to lock yourself out of it, reset it to its factory settings by pressing and holding the Reset button on the back of the WAP for about 10 seconds. Then start the configuration process over again.

Once I'd done this, I disconnected my laptop, shut it down, put the wireless network card back in, booted up and then changed the IP address back to its original, statically assigned value. I then changed the profile of the wireless network card, choosing the same encryption I'd set up in the WAP's encryption config page. I browsed back to the config page and set up MAC address filtering, specifying the MAC address of the wireless network card in my laptop (see below).
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