(Note: This article is a work-in-progress; please add comments and I will fix it as we go.)

To extend your internet connection beyond what would normally be possible using Ethernet, you can use a Wireless Ethernet radio. In this article, we will show you step-by-step how to do this with and for Linux.

This is a picture of our temporary internet café which we set up sometimes in a small bar near the beach where I live. The house is about 300 meters from the bar, and has a radio and antenna on the roof pointed at the bar. It's connected to the Internet with a Linux firewall and an ISDN modem. Note that the antenna is simply placed on a spare bar stool on a chair, and pointed through the window towards the house. This is Sandra checking her email.

The WAP-11 radio by LinkSys (shown above) is a very useful piece of equipment for doing this task. It is standalone, runs on 12 volts, has many different modes of operation, and has two connectors for external antennas. It is available for as little as USD 60 at the time of this writing, and is available in many countries (even though you may pay twice that price).

In order to configure the devices with Linux, you need an Ethernet port on your computer and a web browser. In this article, we will be referencing using SuSE Linux version 9.0, and the Konqueror web browser. You will also need root access if you need to reconfigure your Ethernet port.

To begin, connect one of your radios to the AC mains with the power supply. Make sure the power supply light is on (red). Then connect the Ethernet cable to a spare port on your hub. If you don't have a spare port on your hub, you will probably have to use a crossover cable. Information on how to build a crossover cable can be easily found on the Internet, just do a Google search. If you are connected successfully to your computer, the Link light should be on for both the radio and on your computer's Ethernet card.

The radio's default IP address is 192.168.1.251. If your home/office network is already configured to be on this network (i. e., your computer has an address somewhere between 192.168.1.1 and 192.168.1.254), you can skip the next step (2). My home network is 10.197.99.0, so I have to do the following steps.

1. You need to reconfigure your Ethernet interface so it can talk to the radio. Bring up a terminal shell, login as root, and type these commands:

ifconfig eth0 192.168.1.1
route add -net 192.168.1.0 dev eth0

These two commands let your Ethernet card temporarily become another address and establish a route to the radio, respectively.

It's a good idea to make sure you can talk to the radio at this point. Type:

ping 192.168.1.251

You should see something like this:

BigChicken:/home/willy # ping 192.168.1.251
PING 192.168.1.251 (192.168.1.251) 56(84) bytes of data.
64 bytes from 192.168.1.251: icmp_seq=1 ttl=255 time=3.19 ms
64 bytes from 192.168.1.251: icmp_seq=2 ttl=255 time=0.753 ms
64 bytes from 192.168.1.251: icmp_seq=3 ttl=255 time=0.765 ms

--- 192.168.1.251 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2004ms
rtt min/avg/max/mdev = 0.753/1.571/3.197/1.150 ms

Stop the ping by typing control-c.

If there is no response, check the cabling, make sure the power and link lights are still on and that the link light on the radio blinks as it receives pings. If the response is

From 10.197.99.48: icmp_seq=1 Destination Host Unreachable

You have a routing problem, perhaps your system is set up differently, and you can read the man pages for route to troubleshoot.

2. In addition, if you are using a proxy server, you will need to reconfigure your browser so that it doesn't try to send requests to the proxy when you are accessing the radio. To do this, bring up the browser's option menu (in Konqueror, it's under Settings-->configure Konqueror...), click on Proxy, then add the device under the setup screen to the list of exceptions (local addresses). If you are going to keep the device on your current network, you will also need to add the IP address you intend to assign to it. In my case, I added 192.168.1.251 (current radio address) 10.197.99.222 and 10.197.99.223 (new radio addresses).

3. Now in the URL window of the browser, type

http://192.168.1.251

A small login box should appear. Skip (tab) to the Password box and type admin, then press enter or click Ok. You should see a screen which looks like this:

(click the image for more detail)

Change the IP address to the one you are going to use for your netowrk, then click Apply (not shown, at bottom of browser screen). The radio will reset itself at this point to make the change take effect.

4. As we are making a point-to-point connection, we need to repeat step 3 for the other radio, but this time assigning a different IP address. So disconnect the first radio, connect the second radio to power and Ethernet, and assign the new address.

5.Reconfigure your PC back the way it was:

ifconfig eth0 del 192.168.1.1
route del 192.168.1.0 eth0

6. Now you are ready to configure the radios as repeaters. Connect both radios to power and your network. Bring up two browser windows and type the newly assigned IP addresses in the URL window. Notice near the top of the screen there is some text:

(MAC Address: 00-0C-41-66-40-9C)

My second radio says:

(MAC Address: 00-0C-41-66-40-AB)

Click on the button marked Wireless Bridge for each of the two radio's AP Mode settings, and for each also fill in the MAC address of the other radio. If you fill in the unit's own MAC address, this isn't going to work!. Note that you can't cut and paste the address, as the window expects the hexadecimal string to be filled in as consecutive digits, with no dashes in between. Your browser screen should look something like this:

(click the image for more detail)

7. Now click Accept again and you should be ready to run.

Now we can test the connection. Disconnect the radio you are going to be using as the remote device, and connect it to the remote computer at some distance from the first radio. If the remote computer already works when hardwired to your network, it should just work through the wireless link.

There's still more to tell about installation and tweaking configuration, so stay tuned for updates. Any comments are appreciated.