To restrict users from accessing the system using Centrify free can be easily managed by using the following files
/etc/centrifydc/users.allow /etc/centrifydc/groups.allow /etc/centrifydc/users.deny /etc/centrifydc/groups.deny
1. You have to manually create the the files accordingly and place it at /etc/centifydc. Next you have to line 273 and uncomment the line
..... pam.allow.users: file:/etc/centrifydc/users.allow .....
If you are blocking by groups, you can likewise uncomment the
..... pam.allow.groups: file:/etc/centrifydc/groups.allow .....
2. Flush and Reload Centrify-Free
# adflush # adreload
3. Add users you wish to have access into the system into /etc/centrifydc/users.allow