How to connect two computers directly using a wireless network ?
You can connect two computers wirelessly directly without a router/access point by setting up an ad-hoc wireless network, as long as both have compatible wireless adapters.
Such ad-hoc wireless network is easy to configure, it can be up and running within minutes. The main disadvantage is limited range - wireless coverage is limited by the capability of your wireless adapters, that is usually lower than a router/access point.
You can have up to 9 wireless clients in an ad-hoc wireless network.
Here are some pointers to set up an ad hoc network under Windows XP:
Host computer configuration - you may want to set up ICS (Internet Connection Sharing) on a host computer to share the internet connection. If ICS is enabled on a host computer, the clients will be able to obtain IP adresses automatically from it.
1. Right-click the wireless adapter icon in the system tray and choose "Properties"
2. Choose the "Wireless Networks" tab and click "Advanced".
3. Select the "Computer-to-computer (ad hoc) networks only" option and click "close". Don't tick the "Automatically connect to non-preferred networks" in order to ease the configuration.
4. In the "Preferred networks" dialog, click "Add" to add a new ad hoc wireless network.
5. Name your ad hoc network, try to use "open authentication" without encryption first. Enable WPA or WEP encryption only after testing.
6. After clicking "OK" you should see your newly created ad hoc network in the preferred networks list. You're done with the host computer configuration.
Client Computer configuration
1. Right-click the wireless adapter icon in the system tray and choose properties.
2. You need to set the wireless adapter to "use Windows to configure its network settings" and enable "Computer-to-computer (ad hoc) networks only". Simply follow the same steps as the host computer configuration.
3. Right-click the wireless adapter icon to "view available wireless networks", and you should see your ad hoc wireless netwok name - proceed to connect to it. At that stage you should be able to connect to it.
Note: If you have ICS enabled on the host computer, you can just set each client adapter to obtain an IP address automatically. Otherwise, you will need to allocate a static IP address in the same subnet to each device in the ad-hoc network (done from the Network Adapter properties dialog, TCP/IP v.4).