In order to allow users in the administration, but restrict them from viewing/modifying any secured part of Sitefinity, you should give them the CMS Access
global permission (from the "global permissions" section). Actually, permission="None" does nothing, only "unrestricted
" permissions are processed by Sitefinity. I think what you are trying to do is achievable by using the "Everyone
" role that actually represents all authenticated users.
In short, if you give the CMS Access permission to the Everyone role, the users will be able to enter the administration. In your case, you may want to use the globalGroup.
the Telerik team