Using Authentication

Authentication is a method by which the two ends of the link verify their identity. The Open System authentication is no authentication, i.e. the access point accepts the client as is (modulo any MAC address filtering etc.). Shared Key authentication requires that the client use its WEP key to gain access. There is no mechanism for the access point to prove its identity! And since WEP keys are easily obtained by snooping traffic, little is gained by using authentication. However, if you want to play with it, these are the steps required.

NetGear ME-102

Start the configuration program and select Configure/Wireless and set Auth Type to Shared Key Finally, type W to send the values to the access point, and then go to Commands/Upload to apply the changes to the access point operation.

LinkSys WAP-11 v2.2

Point your browser to the access point, and click on the Advanced tab then on the Wireless tab. Near the bottom set the selection in the Authentication Type line to Shared Key Finally, click on Apply to change the access point operating mode.

Laptop

The change here is quite simple. Edit the file /etc/pcmcia/wireless.opts and change the line

    ESSID="xxxxxxxxxxxxxxxxxxxxxxxxxx"

which was inserted when starting WEP, to

    ESSID="xxxxxxxxxxxxxxxxxxxxxxxxxx managed"

Remove the card, and re-insert, and you now also have authentication of the client to the access point. Of course, this does not authenticate the access point to the client, so you could be tricked into connecting to somebody's rogue access point, with all that implies.

Compatability

I was not able to make the Orinoco card operate in Shared Key mode. I did not try this when the ESSID string was broadcast; perhaps this is a pre-requisite, although I found no specific reference to it.

Version: $Revision: 1.3 $; Updated at 15:47 EST on Tue Apr 11, 2006
Copyright (C) 2002 - 2006, Lindsay Harris