To disable remote login
- 
Open the KDM configuration file for editing. Typically, this file is located at /etc/X11/xdm/xdm-config or /usr/share/config/kdm/kdmrc on Redhat. 
- 
Look for the [XDMCP] section and verify that the Enable property is either not present, commented out, or is set to false, like this: [XDMCP] Enable=false. 
