Reference Manual

HOW TO use the ASUS WL-138G as a Software Access Point on Windows 2000/XP/2003.

HOW TO use the ASUS WL-107G as a Software Access Point on Windows 2000/XP/2003.

HOW TO build your own DSL Wireless Router.

HOW TO convert your Windows 7 Starter Edition Netbook into a DSL Wireless Router. [Details]Added 22. March, 2010.

Overview

The ASUS WL-138G is an 802.11b/g PCI-bus Wireless LAN adapter that comes with a SoftAP configuration utility that allows your Windows XP computer to behave like a regular Wireless LAN Access Point. The WL-138G can also be configured with the generic Marvell Libertas SoftAP utility, so it should be possible to run the adapter in SoftAP mode on Windows 2000 as well.

The ASUS WL-107G is an 802.11b/g PC Card Wireless LAN adapter that will run as a SoftAP on Windows XP when configured with the ASUS configuration utility. The WL-107G uses the Ralink RT2500 chipset and can therefore be switched into SoftAP mode on all Windows 2000 and higher platforms via a generic configuration utility available here.

This document describes how to use NAT32 together with any Wireless LAN adapter in SoftAP mode to give private computers Internet access.

Wireless LAN Adapter Installation Procedure

1. Install the vendor's device driver before inserting the adapter in your system. If you fail to do this, Windows may well install what it thinks is a suitable driver, and you may need to reinstall the correct driver later.

2. All Wireless LAN adapters require a configuration program of some sort. Such a program lets you select the desired adapter mode (Station mode or SoftAP mode) and then lets you adjust the settings for that mode. For example, in Station Mode, the configuration program lets you select an access point you would like to connect to, the security settings you would like to use and so on. In SoftAP mode, the configuration program lets you specify MAC Address access lists, security settings, WDS settings and so on.

3. Windows XP and later start a service called the Wireless Zero Configuration Service, even if you didn't specifically request it. This service is a generic configuration program that is supposed to simplify wireless configuration. However, the program has a major limitation: it does not support SoftAP mode. In addition, it conflicts with vendor-supplied configuration programs that are often installed automatically when the user inserts the CD that is supplied with the adapter. As a result of this conflict, connectivity is lost whenever one of the configuration programs tries to reconfigure the adapter. Therefore, be sure to run the Service Control Manager and disable the WZC Service on your system.

4. Be sure the desired configuration program runs at startup. That way, your WLAN Adapter will be placed in the desired mode each time you boot your system.

5. Always download the latest versions of the driver and configuration utility from the vendor's web site. The software on the supplied CD is usually many months out of date.

Setup and Configuration

The ASUS software is installed by running the setup.exe program contained in the latest version of the support software that you must download from here: ASUS Download.

The ASUS setup program installs a Wireless LAN configuration program called ASUS WLAN Control Center. As described above, be sure you disable the Windows XP wireless configuration service and then start the ASUS Control Center. Select Config and then click the SoftAP tab.

Alternatively, if you need to configure a Windows 2000 system to run in SoftAP mode, you should use one of the other configuration programs mentioned above, all of which are known to run correctly on Windows 2000. Note that I have not found any programs that will support SoftAP mode on Windows 9X platforms.

NAT32 Configuration

Before you configure NAT32, be sure that your Internet Connection has Windows Connection Sharing turned OFF, that IP Forwarding is OFF and that NO Connection Bridges are in place.

Windows Connection Sharing, IP Forwarding and Connection Bridges are not required because NAT32 will do all the necessary sharing and routing.

Configure the TCP/IP protocol bound to the WLAN adapter to use a fixed IP address such as 172.16.1.1, Mask 255.255.255.0 and no gateway. If you have any other wired LANs, be sure they are configured to use some other address range such as 172.16.2.1, Mask 255.255.255.0 and no gateway.

Configure NAT32 to use the WLAN adapter as its Private Interface, and your Internet-connected adapter (which can be a Dial-Up Networking connection) as the Internet Interface. If you have any other private LANs that you wish to connect to the Internet, select them and click "Private Interface" as needed.

Whenever an external computer connects to your Access Point, it should request TCP/IP configuration details via DHCP so that the NAT32 DHCP Server can assign a valid IP address, Network Mask, Gateway and DNS Server address. The external computer will then have access to all computers on the private network(s) and to the Internet. If you don't want to allow some or all of the private computers to access the Internet, simply open the NAT32 Admin window and block the desired machines.

If NAT32 is connecting several private networks, be sure to add the command: setnb on to your user.txt file. This will ensure that all machines on each private LAN appear in each others Network Neighborhood.

Security

Most SoftAPs support WEP Encryption, Access Control via a MAC-address list and Traffic Isolation.

Because WEP Encryption has some known security flaws, I usually turn it off and run a VPN server on the NAT32 computer. All wireless clients then have to first set up a secure VPN connection to the server in order to obtain Internet access.

MAC-address access control is an effective way of controlling access to your wireless LAN but offers no protection against eavesdropping.

Traffic Isolation allows wireless machines to see the SoftAP adapter but not each other. This is a useful feature if you want to prevent the wireless machines from viewing the Windows Network Neighborhood.

Be sure to enable a firewall on the Internet Connection to block unwanted traffic. The firewall must allow NAT32 to communicate without restrictions.

Internet Connections

The easiest way to connect the machine to the Internet is via a low-cost DSL Modem such as the D-Link DSL-200 Revision B. This modem installs without a hitch on XP SP2 and gives good performance, even on a recycled 400 MHz laptop. Of course, other technologies such as Cable Modems, ISDN or 56K Dial-Up Connections can be used if DSL is not available in your area.

Additional Software

You can enhance the features of the system by running software such as Apache, mySQL, Filezilla and Mercury, downloadable in one convenient package from here.

To manage and control the system, simply install UltraVNC and then connect to it from anywhere via your web browser.

For optimal performance and security, do not install any other software on the machine, particularly packages like Microsoft Office and the .NET runtime, as these packages are known to cause Registry bloat, often a major cause of poor performance.

Performance

Initial tests with two external computers connected showed that networking performance was excellent. Range was also good, and an external antenna can be connected to some adapters to extend the range if needed.

Wireless Bridges

In some situations, it may be necessary to use a WDS-capable wireless bridge to extend the range of your wireless LAN. The ASUS WL-107G, when configured with this configuration utility, supports WDS without problems. Simply run the utility and select the WDS tab. Then click Enable WDS Policy and enter the MAC Address of your wireless bridge device. Then click Apply. Be sure that the WL-107G and your wireless bridge use the same channel.

Interestingly, the Apple Airport Express works perfectly as a wireless bridge with the WL-107G, even though Apple states that WDS only works with other Airport products. Be sure to configure it with the Airport Admin tool as a relay base station and then enter the MAC address of the WL-107G in the Main Airport ID field. You will find these settings under the WDS tab. Then click Update and wait a minute or two for the Airport Express to reboot.

Summary

SoftAP mode is a very useful feature that allows any PC to behave just like a hardware Access Point but with all the added features of NAT32, such as user administration, traffic and bandwidth management, and multiple Internet connection support. When installed on a laptop computer, a full-featured DSL Router can easily be constructed with all the benefits and flexibility of a configurable Windows machine, as well as low power consumption.

SEE ALSO

PCTEL SoftAP, User Administration
[Edit] [Back]