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Setting up Wireless Cards on FreeBSD
Pages: 1, 2

If all of your network devices are configured identically, you should be able to assign IP addresses normally and ping. If you can't, one of these settings is probably wrong.



One other issue might arise, and that's frequency. All the wireless stations must be on the same frequency to communicate. There are 14 different 802.11b frequencies. If you find that your network shuts down when you're microwaving a burrito, try a different frequency. You can do that with:

wicontrol -f frequencynumber

The default frequency on cards sold in the US is 3.

If you have an access point, you'll need to configure that as well. In addition to allowing you to bridge your wireless and Ethernet networks, an access point can allow you to control which MAC addresses can connect to your network, and can act as a central point for monitoring. I used the Apple Airport base station as an access point, with great success. It speaks SNMP, so if I wanted to get really funky I could monitor throughput and connections. Best of all, the Airport can be configured from your FreeBSD system with the help of the "airport" tool (/usr/ports/net/airport). Many other access points only have Windows-based configuration tools.

Also in Big Scary Daemons:

Running Commercial Linux Software on FreeBSD

Building Detailed Network Reports with Netflow

Visualizing Network Traffic with Netflow and FlowScan

Monitoring Network Traffic with Netflow

Information Security with Colin Percival

I only had one problem with the airport tool; some of the input windows were too small to hold text. This turned out to be a bug in Java's Swing classes; if the application window isn't large enough to hold the fields, the fields shrink like this. Expand the application window, and input boxes will suddenly appear.

From there it's fairly simple. Hit the "discover devices" button. It will scan the network and look for Airports. When it finds one, it'll open a window containing the IP address. Enter the IP address and the SNMP community string ("public" by default), and you can retrieve the Airport's configuration.

Don't try to create an Airport configuration from scratch in the airport tool. The tool's author freely admits that the Airport has certain configuration requirements that the program cannot set. This information can only be retrieved from a running Airport. Retrieve a good configuration before you try to make any changes.

You need to configure your access point in exactly the same way as your network cards. Give it an IP address on your local network, and set the encryption keys, network name, and channel. You don't need to set the network type -- if you have an access point, you are either running in infrastructure mode or doing something really, really weird.

Take a look at the "bridging functions" tab. This is where you control how the Airport integrates with your existing network. To simply add wireless functions to an existing network, select "Act as transparent bridge."

When everything looks correct to you, hit "Update Base Station." This will reconfigure the Airport. If you did everything right, you can walk down the block reading oreillynet.com on your laptop. I plan to mail this article from the park at the end of the street.

Wireless is just a little bit different than regular Ethernet. Once you understand the requirements, however, setting up wireless is much less confusing. It's well worth the effort, though. My only regret about my wireless setup is that it's too cold outside for me to sit on the patio while writing my column. Thanks, Michigan.

Michael W. Lucas


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