AirPort WEP Key Slot Problems: Incompatibility with some Windows networks

MacFixIt reader Guy Kuo reports a limitation in Apple's AirPort devices that prevents proper access to Windows-based wireless networks using a WEP slot key other than "1." In essence, if the wireless network uses any slot number other than "1" (2, 3, or 4), an AirPort-enabled Mac will be unable to join without the use of a third-party wireless access device not subject to the limitation.

Kuo writes: "Although WEP security is minimal one often finds WEP active in networks. I've run into a limitation of Apple's 802.11b and 802.11g driver implementation that practically excludes Macintoshes from connecting to some wireless networks that use non-Apple base stations.

"I'm not talking about the usual ASCII vs hex WEP password issues, but the WEP key slot number. Basically, Apple equipment always assumes the WEP password is associated to the first key slot. There are 4 slots allowed under 802.11 specs and every single PC based wireless solution lets you specify which slot number with which a WEP key is associated. Both WEP key and the slot number must agree between client and base station. WiFi alliance compliance only tests slot number one and Apple has always supported ONLY slot one in their drivers.

"If a network is configured to use WEP key slots 2, 3, or 4, Macintoshes are unable to join the network even if one enters the correct WEP password. The RF signal indicator on the Mac will indicate a connection, but no packets will get through due to the Mac blindly associating the WEP key to slot #1. With Apple bases stations, this never is a problem because the Airport or Airport Extreme base station assumes slot#1. It is not so much fun when you walk into an organization that has its network set up for any other key slot#. All the PC's can connect because PC's all allow specification of the slot# in addition to the WEP key. Us poor Mac users are left in the cold ...... mostly anyway.

"I did find one very kludgey work around. A D-Link USB to 802.11b dongle along with their 1.4.7 driver adds an alternative 802.11 connection to my Powerbook's Airport Extreme. The D-Link driver DOES allow selection of a WEP Key slot so I can connect to a network that uses WEP in the second key slot. It's not completely stable a solution and is a pain to plug in a dongle when the Powerbook has an otherwise perfectly usable 802.11g system.

"Inability to select WEP Key Slot number is has become an unnecessary limitation that hobbles Mac's in my work place. Every single PC can deal with alternative WEP key slots, but Apple hardware can't. Sure, I could try to get an IT department to reconfigure all the base stations (about 70 to 100 stations) to use slot#1, but all the PC users are already happy, it would be a lot of work, it would break the current PC connections. You can predict how far that will get."

If this issue is affecting you, please drop us a line at late-breakers@macfixit.com.

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