Windows Wireless Zero Configuration: Five Steps to Sanity Coping with XP's WLAN Management Software Ron Pacchiano
With the release of Windows XP, Microsoft tried to make configuring and connecting to wireless networks easy for everyone. They partially succeeded. The Wireless Zero Configuration service is the “brains” behind managing wireless connections with Windows. Unfortunately, WZC does not always make sane decisions, which can cause sensations of frustration and annoyance, not to mention itching and burning.
Access Point Whack-a-Mole
In some spaces where wireless access is available, multiple access points are used to blanket a large area. Frequently these access points all broadcast the same network name, or SSID. Wireless Zero Configuration is programmed to assume this is the case – so, when it sees more than one AP with the same SSID, it automatically connects to the one with the strongest signal.
Not a bad strategy on paper. But what if two APs are broadcasting the same SSID and are not on the same network? WZC will connect to the stronger one, whether you want it to or not, which might hook you up to the wrong network, possibly interrupting an existing session with your desired network.
Of course, if you manage your own wireless network, you can simply change its SSID to a unique name. But maybe you’re in a public space, or a zone managed by your workplace or a provider broadcasting an SSID of their choosing.
WZC will not distinguish access points with the same SSID. They appear only as one in Windows’ “Available Wireless Networks” menu. So you can’t force Windows to connect to a particular AP.
In this troubling scenario, the only solution that might work is to ditch WZC in favor of a third-party wireless client manager. Most wireless network adapters, whether external or internal, include a connection manager provided by the vendor – Linksys/Cisco, Orinoco/Proxim, Netgear, etc. Typically you can’t use both your vendor’s connection manger and WZC at the same time. Skip ahead to “Ditching WZC” for instructions on disabling the Windows connection manager.
Unfortunately, not all vendor-provided client managers solve this particular scenario, either. Unlike WZC, they may display multiple AP’s which are broadcasting the same SSID. But like WZC, they may not allow for forcing an association with one. In that case, if there is a workable solution out there, we’d like to know!
Hidden SSID Syndrome
By default, most access points broadcast their SSID. This allows your connection manager to see their presence and tell you, "Hey, buddy: this access point is in range." Some people prefer to hide their SSID by configuring their access point not to broadcast. In this case, you manually set the SSID in your connection manager to link the connection.
The problem with Wireless Zero Configuration occurs if a second AP is also within range. If that AP is broadcasting its SSID, WZC will attempt to connect to it – even if you’ve told it that your AP with the hidden SSID is your preferred network. Whether or not WZC can establish a connection with the more promiscuous AP, its attempts can cause instability in your link.
Disabling SSID broadcasting is sometimes suggested as a security precaution. The theory is that your AP won’t advertise its presence to nearby snoops. In fact, this doesn’t provide much security at all. Whether or not it broadcasts its SSID, the AP includes the SSID in transmission packets which are easily sniffed out. In reality, disabling your SSID is no more secure than taping a broom handle across your steering wheel, hoping that thieves will mistake it for The Club. Secure your access point with WPA, or a MAC address filter. Enable SSID broadcasting, and WZC will treat you better.
Of course, the AP with the hidden SSID may not be yours to configure. If you can’t manage the access point yourself, a kludgier solution is to knock WZC senseless. Skip ahead to “The WZC Two-Step” on the next page for details on how to disable WZC after it has established the connection.
Whoosawhatsit? 802.1x Authentication
Many home and small organizations secure their wireless networks using WEP or, preferably, WPA. But some institutions use the enterprise-oriented IEEE 802.1X authentication framework, which Windows XP supports natively.
Unfortunately, if you don’t use 802.1X on your wireless network, Wireless Zero Configuration may interrupt your connection when it periodically attempts to perform 802.1X authentication against your associated access point.
To prevent interruptions in connectivity, disable 802.1X authentication for your wireless network adapter. In Windows, open the Network Connections control panel. Locate your wireless adapter, double-click it, and choose Properties and then Wireless Networks. You should see a tab labeled Authentication, in which you can disable “Enable IEEE 802.1X Authentication for this network”.
