Difficulty forwarding X via SSH to Windows

HappyAndBreathe · 2021-11-20 22:39:53

I have a working SSH server which I connect to by use of an SSH key.

On the Windows client machine I have VcXsrv running, and in its logs it says this.

winClipboardThreadProc - DISPLAY=127.0.0.1:0.0

I have followed the guide on the Arch Wiki SSH page (namely have the two packages installed, ensure those config settings are set, and the service is restarted).

https://wiki.archlinux.org/title/OpenSSH#X11_forwarding

With a fresh Windows Terminal window (running PowerShell) I get this.

PS C:\Users\User> ssh -X user@laptop
Last login: Sat Nov 20 22:30:36 2021 from 192.168.0.25
~ firefox
Error: no DISPLAY environment variable specified

I then try the -Y flag instead, and I get the same result.

As suggested on the Arch Wiki, I try this.

~ xhost +
xhost:  unable to open display ""

Then I do a bit of Googling and see that I should set environment variables in PowerShell first before running the SSH command.

set DISPLAY=localhost:0.0

But this changes nothing and I get the same result.

The only thing I can think of whereby my X setup is not "vanilla" was adding this file to ensure the screen powers off.

#file /etc/X11/xorg.conf.d/99-customdpms.conf
Section "ServerFlags"
    Option "StandbyTime" "0"
    Option "SuspendTime" "0"
    Option "OffTime" "1"
    Option "BlankTime" "0"
EndSection

Any thoughts on what I should do? More than happy to provide extra data.

Last edited by HappyAndBreathe (2021-11-20 22:41:55)

seth · 2021-11-21 09:46:01

~ xhost +
xhost:  unable to open display ""

Where exactly are you doing this? Is there actually an X11 server running on the remote system?

HappyAndBreathe · 2021-11-21 10:28:02

On the Arch machine which is running the SSH server.

For that particular command, I SSH'd into the server and tried the command.

The Arch machine is setup with a full LXDE environment which is working well.

seth · 2021-11-21 14:19:31

You need (if so) open the X11 server (ie. on your windows machine)

I assume you also set "set DISPLAY=localhost:0.0" on the archlinux system (the remove host where the X11 clients run)?
That's wrong - the $DISPLAY on the ssh server must point to the X11 server (which is typically the ssh client, your windows machine) and is typically exported by "ssh -Y"

So run "ssh -Y user@laptop" and check "echo $DISPLAY" - and try a simpler testcase than FF for the beginning (eg. xterm)

HappyAndBreathe · 2021-11-21 15:44:13

Hi Seth. First off, thanks a bunch for your help, I really appreciate.

So without setting any variables in Powershell, I SSH into my Arch machine with the -Y flag.

When I echo $DISPLAY, I get the result "localhost:10.0" which I didn't expect.

In any case, with the X Window Server application (VcXsrv) on the Windows client, I set the display to 10, too.

After that, running xclock gives this result.

connect localhost port 6000: Connection refused
Error: Can't open display: localhost:10.0

seth · 2021-11-21 16:07:15

In any case, with the X Window Server application (VcXsrv) on the Windows client, I set the display to 10, too.

I have zero experience w/ VcXsrv but
1. don't set the DISPLAY on the X11 server (VcXsrv) to match the client value - you expect the server to communicate the proper display to the client. If you had previously configure the VcXsrv display to be 10 and that got communicated, that's however good.
2. "localhost:10.0" is wrong for sure (I assume VcXsrv confuses "localhost" for a domain), because no X11 server is running on "localhost" (ie. *this* machine) from the X11 client (ssh server, archlinux) perspective - try to set the client DISPLAY (ie. on the remote system) to the IP of the windows system.

Arch Linux

#1 2021-11-20 22:39:53

Difficulty forwarding X via SSH to Windows

#2 2021-11-21 09:46:01

Re: Difficulty forwarding X via SSH to Windows

#3 2021-11-21 10:28:02

Re: Difficulty forwarding X via SSH to Windows

#4 2021-11-21 14:19:31

Re: Difficulty forwarding X via SSH to Windows

#5 2021-11-21 15:44:13

Re: Difficulty forwarding X via SSH to Windows

#6 2021-11-21 16:07:15

Re: Difficulty forwarding X via SSH to Windows

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