Having trouble authenticating to that website on the intranet? Try clearing out your cache of Kerberos tickets on your computer. . .
“klist tickets” will list all the tickets you currently have
“klist purge” will clear them out
More information at http://technet.microsoft.com/en-us/library/cc738673.aspx
And you can download the tool at http://www.microsoft.com/downloads/details.aspx?familyid=9d467a69-57ff-4ae7-96ee-b18c4790cffd&displaylang=en