You will need to make sure the RHEL server is running in run-level 5 so that
this line in inittab will run:
# Run xdm in runlevel 5
x:5:respawn:/etc/X11/prefdm -nodaemon
You may need to configure xdm (or gdm) to allow incoming xdmcp requests and
configure eXceed to use XDMCP.
There are probably other ways to make it work, but we stopped using eXceed in
favor of VNC 5+ years ago...
I highly recommend VNC, the server (which runs on the SERVER - imagine that!)
comes with RHEL and the client (viewer) is free. It can do anything eXceed can
do (in my experience) and is more efficient because of the method it uses to
update the display. Plus, once you start the vncserver process you can
disconnect the client and re-connect from elsewhere - a network glitch won't
crater your session! The Enterprise (paid) version of VNC can do SSO via
Kerberos/AD and will encrypt your connection, too.
Check out: www.realvnc.com
Good luck,
Kevin