There are two sets of permissions that must be in sync for your CMS site to operate properly. One set of permissions are set in CMS, through Site Manager. The other set of permission are the specific Access Control Lists (ACLs) for the directory where your solution files are stored. If you change the ACLs on the project folders, it's possible to prevent users from accessing the site. For example, if we were to change the ACLs for our templates folder in the BOTS site to disallow the CMS guest account, our anonymous access would stop working; CMS would still allow access to the content, but since the template can't run, the site won't operate. However, if you create a special folder in your project to hold templates that are appropriate only for postings accessed by certain individuals, then it's possible to block access to the postings based on those templates by changing the ACLs on that folder. This could work for you or against you depending on your situation. Using this technique, you can create a more secure site, or a completely inaccessible site if you don't set the permissions correctly.