X11 tunnel over ssh and then rsh

[Roberto Nunnari]

Hello list.

I have this scenario

1) host A with X server
2) host B with ssh server but without X server
3) host C with rsh server and X client programs but without X server
(on host C there's also an ssh server, but in our case, users
have to use rsh)

now, I need to connect from host A to host B with:
A$ ssh -Y B (-Y or -X, to create a X tunnel)
and then from host B to host C with:
B$ rsh C
and on host C I need to run an X client like:
C$ xterm

Now, I would like the users not to have to set the
DISPLAY env var on host C, as they tend to forget
and also some user's X server don't accept plain
X connections..

Is there a way that I could configure host B to somehow
expose to host C the X tunnel to host A? From host
B I have access to the users' homes on host C and I could
place there some script to set the DISPLAY env var on user
login.

B$ echo $DISPLAY
on host B gives back something like localhost:16.0,
but if on host C I enter:
C$ export DISPLAY=B:16.0
C$ xterm
it doesn't work.. probably host C doesn't expose a
network socket but maybe a unix socket for the X tunnel..

Any help/hint greatly appreciated.

Best regards.
Robi