I'm running FreeRADIUS Version 2.2 and Mysql  for VPN access authentication on ubuntu 14.04, the Windows Phone8.1 clients send username as Windows Phone\username, the Mysql radcheck table doesn't include Windows Phone\, so access authentication failed. I 've googled this issue, and haven't found anything that worked. I have tried the methods in this post: http://lists.freeradius.org/pipermail/freeradius-users/2011-March/052650.html, but problem still exists.