SPNego not working?

After installing Duet, there could be an issue getting SPNego to work.  The issue can manifest in the following way:

Browsing to http://servername:50100/osp/TicketIssuer will result in a successful response.

Browsing to http://servername.fqdn.domain:50100/osp/TicketIssuer will result in a 401 “not authorized”.

The problem is documented in KB Article 899417.  To make this work as expected make sure that the key FEATURE_ENSURE_FQDN_FOR_NEGOTIATE_KB899417 is created in the following location:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl

Under that key, add the DWORD keys explorer.exe and iexplore.exe with a value of 1.

Restart the browser and it should work as expected.