Summary: X11 question, how to find out display#?

From: Ju-Lien Lim (
Date: Wed Jan 28 1998 - 16:45:21 CST

My thanks to everyone who responded...unfortunately,
I was not looking for how to set the DISPLAY but
rather how get the display# (which is part of how you
set the DISPLAY, e.g.
DISPLAY=hostname:display#:screen#). I won't list
everyone's names but you know who you are.

According to Frank Cusack <>,
what is the likely culprit is that I don't have all
the X files loaded (quite likely as I inherited this
machine and unfortunately, I can't put patches, fix
all its problems since it's got to be up just about
24 hours....<arg>). I'll hopefully figure out what's
missing and see if I can get around it; otherwise I
may try and pull a copy of sshd from another machine
and hope that it fixes it.

Here is what Frank writes:

This is a question for an ssh list, not the sun list.
But anyway, the only time I've seen this is when a)
you don't have the X stuff installed on your machine
- it's possible to install some of it but not all; or
b) you compiled ssh without the X stuff being in the
path. IIRC, the X stuff needs to be located at
compile time.

You have no display set because ssh couldn't do
xauth. Otherwise, it would have set it to something
like G16:0.5

You don't need to "just set the correct display", ssh
will do this for you, it forwards a local X
connection over the ssh connection. If you set the
display (just like any other env variable) to your
own machine, the connection will not go through ssh.

The SSH FAQ and web pages are the best place to get
your answers.

Original Question:
I have a machine in CT and I run ssh (instead of
rlogin/telnet) to a machine (G16) in another state.
Anyways, once I get to G16, I'd like to be able to
open multiple xterms. However, I notice that I get
the following message when I log into the machine:

Warning: Remote host denied X11 forwarding, perhaps
xauth program could not be run on the server side.

Furthermore, when I type "xhost" on G16, I get the
G16 => xhost
xhost: unable to open display ""

How do I enable X11 forwarding? Also, I really just
need to set the correct display, but don't how to
find out the display# that is part of setting the
i.e. DISPLAY=hostname:display#.screen#) to set it to.
 How do I find out the display#?

Thanks again.

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