While Windows 2000 drivers exist for 802.1x wireless hardware, Windows does not natively support 802.1x security protocols. This is a problem for administrators who want to use Windows 2000 clients in a secured 802.11 environment.
Often the only way to do this is to use a third-party security solution, often provided by the manufacturers of the wireless hardware. Unfortunately, if different machines are using different manufacturer's hardware, the keylengths are often incompatible. Windows XP solves this problem by providing consistent keylength and encryption support across hardware products, but upgrading to Windows XP may not be a possibility.
To that end, Microsoft has produced a support package that adds 802.1x support to Windows 2000. Many admins who are trying to get Win2K machines networked don't even know of it, since it has gone largely unreported. The full details about the fix are in Microsoft Knowledge Base article Q313664, and a quick link to downloading the package (for the English version of Windows 2000) can be found here.
There are several limitations. First, the fix does support IAS RADIUS authentication, but requires that Windows 2000 Service Pack 2 or higher be present, as well as a number of other security-related patches. For the best possible results, the fix should only be installed on a machine that has the most recent service pack and security hotfixes.
Second, a number of features native to Windows 2003's 802.1x support are not available in this fix. There is no Wireless Zero Configuration support, so wireless connections have to be set up by hand. Wireless configuration by Group Policy is also not supported, and only one wireless network adapter at a time will work.