Windows 10 with November Update Having Trouble Negotiating Access to Radius Servers

Here’s one that you should be aware of. For those running Radius servers in their organizations, there’s an issue that accompanies the Windows 10 November Update.

According to the title of KB3121002, “Windows 10 devices can't connect to an 802.1X environment.” The title is a bit misleading because it seems all-encompassing. The true nature of the problem, as the KB article states, is a bug in how Radius server implementations handle TLS 1.2.

The KB article lists out the known affected Radius servers and that a fix is coming and in some cases is already available from Radius. However, to work around the issue for now, Microsoft is suggesting a registry modification. The modification will allow computers with Windows 10 November Update to connect, but also potentially leaves them vulnerable earlier TLS 1.0 vulnerabilities – so tread with care.