RedHat 6.2 is the same as RedHat 6.1, but you must also edit the file /etc/X11/xdm/xdm-config. See at the end. By default the display manager won't work over the network (won't serve X terminals). You must comment the last line to enable network operation.
You must do it only if you are using xdm or kdm (KDE login screen).