On LAN, I'm trying to run Emacs on another machine, as shown below:

$ ssh -X werner@192.168.10.100
$ emacs

At this moment, I noticed the following information:

Display localhost:10.0 unavailable, simulating -nw

As a result, Emacs will run in console mode and can't be able to
communicate with X.

Any hints for solving this problem?

Regards,
HY

On 7/27/21 7:30 AM, hongy...@gmail.com wrote:
> Any hints for solving this problem?

What is the DISPLAY environment variable set to?

Do any X11 programs work through SSH?

--
Grant. . . .
unix || die

On Tue, 27 Jul 2021 09:30:48 -0400, hongy...@gmail.com <hongyi.zhao@gmail.com> wrote:

> On LAN, I'm trying to run Emacs on another machine, as shown below:
>
> $ ssh -X werner@192.168.10.100
> $ emacs
>
> At this moment, I noticed the following information:
>
> Display localhost:10.0 unavailable, simulating -nw
>
> As a result, Emacs will run in console mode and can't be able to
> communicate with X.
>
> Any hints for solving this problem?

On the system you're connected to, in /etc/ssh/sshd_config is the config set to ...
X11Forwarding yes

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

"hongy...@gmail.com" <hongyi.zhao@gmail.com> writes:
> On LAN, I'm trying to run Emacs on another machine, as shown below:
>
> $ ssh -X werner@192.168.10.100
> $ emacs
>
> At this moment, I noticed the following information:
>
> Display localhost:10.0 unavailable, simulating -nw
>
> As a result, Emacs will run in console mode and can't be able to
> communicate with X.
>
> Any hints for solving this problem?

Apparently $DISPLAY is being set to "localhost:10.0", which is typical.

This is unlikely to be specific to emacs. I presume other X client
programs fail similarly, but to verify try running "xlogo" or "xclock".

Try running "xdpyinfo". (Warning: It produces several thousand lines of
output on my system).

It's possible that "ssh -Y" would avoid the problem. It's worth trying,
but be sure to read the documentation, since it bypasses some security
checks. (It might be acceptable if the LAN is entirely under your
control, though others might disagree with that.)

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips
void Void(void) { Void(); } /* The recursive call of the void */

On Wednesday, July 28, 2021 at 2:33:54 AM UTC+8, Grant Taylor wrote:
> On 7/27/21 7:30 AM, hongy...@gmail.com wrote:
> > Any hints for solving this problem?
> What is the DISPLAY environment variable set to?

On server side:

werner@X10DAi:~$ echo $DISPLAY
:1

On client side, it's empty:

$ echo $DISPLAY

$

> Do any X11 programs work through SSH?

I run ssh in verbose mode (-v):

$ ssh -vX werner@192.168.10.100

Then xterm also fails to open display, and it says that X11 connection
rejected because of wrong authentication. I've enabled the
following options on server and client sides:

On server side:

$ grep ^X11Forwarding /etc/ssh/sshd_config
X11Forwarding yes

On client side:

$ grep '^[ ]*ForwardX11' /etc/ssh/ssh_config
ForwardX11 yes

On Wednesday, July 28, 2021 at 3:34:45 AM UTC+8, David W. Hodgins wrote:
> On Tue, 27 Jul 2021 09:30:48 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
>
> > On LAN, I'm trying to run Emacs on another machine, as shown below:
> >
> > $ ssh -X wer...@192.168.10.100
> > $ emacs
> >
> > At this moment, I noticed the following information:
> >
> > Display localhost:10.0 unavailable, simulating -nw
> >
> > As a result, Emacs will run in console mode and can't be able to
> > communicate with X.
> >
> > Any hints for solving this problem?
> On the system you're connected to, in /etc/ssh/sshd_config is the config set to ...
> X11Forwarding yes

Yes:

$ grep ^X11Forwarding /etc/ssh/sshd_config
X11Forwarding yes

On 7/27/21 7:32 PM, hongy...@gmail.com wrote:
> On server side:
>
> werner@X10DAi:~$ echo $DISPLAY
> :1

Did you run that from your SSH connection? Or directly on the server?

:1 /may/ be okay for a remote connection. But it may also be a
reference to a local / physical display on the server.

> On client side, it's empty:
>
> $ echo $DISPLAY

I would have expected the client to have a DISPLAY variable set.
ESPECIALLY if running it form in a GUI terminal emulator.

> I run ssh in verbose mode (-v):

Verbose mode shouldn't change the behavior of X11 forwarding. But it
will give more information.

> Then xterm also fails to open display, and it says that X11 connection
> rejected because of wrong authentication.

Okay. That's sort of what I was expecting.

You can use the 'xhost' command to allow other clients to connect
bypassing the ~/.Xauthority (?) cooky. E.g.

xhost +192.0.2.1

That should allow 192.0.2.1 to connect to your local X11 display.

N.B. You can remove the IP and just use "+" to allow all IPs to connect
too.

Use the following command to remove permission:

xhost -

N.B. My understanding is that the xhost permissions are non-persistent.

> I've enabled the following options on server and client sides:

That means that OpenSSH is configured to allow X11 forwarding.

As Keith mentioned, the "-Y" option may help.

--
Grant. . . .
unix || die

On Wednesday, July 28, 2021 at 3:58:13 AM UTC+8, Keith Thompson wrote:
> "hongy...@gmail.com" <hongy...@gmail.com> writes:
> > On LAN, I'm trying to run Emacs on another machine, as shown below:
> >
> > $ ssh -X wer...@192.168.10.100
> > $ emacs
> >
> > At this moment, I noticed the following information:
> >
> > Display localhost:10.0 unavailable, simulating -nw
> >
> > As a result, Emacs will run in console mode and can't be able to
> > communicate with X.
> >
> > Any hints for solving this problem?
> Apparently $DISPLAY is being set to "localhost:10.0", which is typical.
>
> This is unlikely to be specific to emacs. I presume other X client
> programs fail similarly, but to verify try running "xlogo" or "xclock".

Both "xlogo" and "xclock" run correctly.
> Try running "xdpyinfo". (Warning: It produces several thousand lines of
> output on my system).

werner@X10DAi:~$ xdpyinfo
name of display: localhost:10.0
version number: 11.0
vendor string: The X.Org Foundation
vendor release number: 12008000
X.Org version: 1.20.8
maximum request size: 16777212 bytes
motion buffer size: 256
bitmap unit, bit order, padding: 32, LSBFirst, 32
image byte order: LSBFirst
number of supported pixmap formats: 7
supported pixmap formats:
depth 1, bits_per_pixel 1, scanline_pad 32
depth 4, bits_per_pixel 8, scanline_pad 32
depth 8, bits_per_pixel 8, scanline_pad 32
depth 15, bits_per_pixel 16, scanline_pad 32
depth 16, bits_per_pixel 16, scanline_pad 32
depth 24, bits_per_pixel 32, scanline_pad 32
depth 32, bits_per_pixel 32, scanline_pad 32
keycode range: minimum 8, maximum 255
focus: window 0x3805921, revert to Parent
number of extensions: 30
BIG-REQUESTS
Composite
DAMAGE
DOUBLE-BUFFER
DPMS
DRI2
GLX
Generic Event Extension
MIT-SCREEN-SAVER
MIT-SHM
NV-CONTROL
NV-GLX
Present
RANDR
RECORD
RENDER
SECURITY
SHAPE
SYNC
X-Resource
XC-MISC
XFIXES
XFree86-DGA
XFree86-VidModeExtension
XINERAMA
XINERAMA
XInputExtension
XKEYBOARD
XTEST
XVideo
default screen number: 0
number of screens: 1

screen #0:
dimensions: 1920x1080 pixels (602x343 millimeters)
resolution: 81x80 dots per inch
depths (7): 24, 1, 4, 8, 15, 16, 32
root window id: 0x1dd
depth of root window: 24 planes
number of colormaps: minimum 1, maximum 1
default colormap: 0x20
default number of colormap cells: 256
preallocated pixels: black 0, white 16777215
options: backing-store WHEN MAPPED, save-unders NO
largest cursor: 256x256
current input event mask: 0xda0033
KeyPressMask KeyReleaseMask EnterWindowMask
LeaveWindowMask StructureNotifyMask SubstructureNotifyMask
SubstructureRedirectMask PropertyChangeMask ColormapChangeMask
number of visuals: 132
default visual id: 0x21
visual:
visual id: 0x21
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x22
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x24
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x25
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x26
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x27
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x28
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x29
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x2a
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x2b
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x2c
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x2d
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x2e
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x2f
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x30
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x31
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x32
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x33
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x34
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x35
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x36
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x37
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x38
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x39
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x3a
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x3b
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x3c
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x3d
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x3e
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x3f
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x40
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x41
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x42
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x43
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x44
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x45
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x46
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x47
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x48
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x49
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x4a
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x4b
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x4c
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x4d
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x4e
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x4f
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x50
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x51
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x52
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x53
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x54
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x55
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x56
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x57
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x58
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x59
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x5a
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x5b
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x5c
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x5d
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x5e
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x5f
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x60
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x61
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x62
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x63
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x64
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x65
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x66
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x67
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x68
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x69
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x6a
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x6b
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x6c
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x6d
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x6e
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x6f
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x70
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x71
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x72
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x73
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x74
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x75
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x76
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x77
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x78
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x79
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 11 bits
visual:
visual id: 0x23
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x7a
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x7b
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x7c
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x7d
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x7e
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x7f
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x80
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x81
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x82
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x83
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x84
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x85
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x86
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x87
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x88
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x89
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x8a
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x8b
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x8c
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x8d
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x8e
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x8f
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x90
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x91
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x92
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x93
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x94
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x95
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x96
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x97
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x98
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x99
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x9a
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x9b
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x9c
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x9d
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x9e
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x9f
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0xa0
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0xa1
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0xa2
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0xa3
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0xa4
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits

"hongy...@gmail.com" <hongyi.zhao@gmail.com> writes:
> On Wednesday, July 28, 2021 at 2:33:54 AM UTC+8, Grant Taylor wrote:
>> On 7/27/21 7:30 AM, hongy...@gmail.com wrote:
>> > Any hints for solving this problem?
>> What is the DISPLAY environment variable set to?
>
> On server side:
>
> werner@X10DAi:~$ echo $DISPLAY
> :1
>
> On client side, it's empty:
>
> $ echo $DISPLAY
>
> $

That seems inconsistent with your original post. You said you got this
message from emacs:

Display localhost:10.0 unavailable, simulating -nw

which strongly implies that $DISPLAY was set to "localhost:10.0", at
least in your emacs process.

Try `echo $DISPLAY` and `emacs` from the same shell process. If you get
an empty string from the first (it's more likely that $DISPLAY is not
set than that it's set to the empty string) and "Display localhost:10.0
unavailable, simulating -nw" from emacs, then something very strange is
going on.

What does `env | grep '^DISPLAY='` print?

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips
void Void(void) { Void(); } /* The recursive call of the void */

"hongy...@gmail.com" <hongyi.zhao@gmail.com> writes:
> On Wednesday, July 28, 2021 at 3:58:13 AM UTC+8, Keith Thompson wrote:
>> "hongy...@gmail.com" <hongy...@gmail.com> writes:
>> > On LAN, I'm trying to run Emacs on another machine, as shown below:
>> >
>> > $ ssh -X wer...@192.168.10.100
>> > $ emacs
>> >
>> > At this moment, I noticed the following information:
>> >
>> > Display localhost:10.0 unavailable, simulating -nw
>> >
>> > As a result, Emacs will run in console mode and can't be able to
>> > communicate with X.
>> >
>> > Any hints for solving this problem?
>> Apparently $DISPLAY is being set to "localhost:10.0", which is typical.
>>
>> This is unlikely to be specific to emacs. I presume other X client
>> programs fail similarly, but to verify try running "xlogo" or "xclock".
>
> Both "xlogo" and "xclock" run correctly.
>
>> Try running "xdpyinfo". (Warning: It produces several thousand lines of
>> output on my system).
>
> werner@X10DAi:~$ xdpyinfo
> name of display: localhost:10.0
> version number: 11.0
> vendor string: The X.Org Foundation
[993 lines deleted]

I guess I should have said that we don't need to see all the output.
It was basically a test to see whether the display is there.

>> It's possible that "ssh -Y" would avoid the problem. It's worth trying,
>> but be sure to read the documentation, since it bypasses some security
>> checks. (It might be acceptable if the LAN is entirely under your
>> control, though others might disagree with that.)
>
> I tried with:
>
> $ ssh -Y werner@192.168.10.100
>
> But still meet the following msg:
>
> werner@X10DAi:~$ emacs
> Display localhost:10.0 unavailable, simulating -nw

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips
void Void(void) { Void(); } /* The recursive call of the void */

On Wednesday, July 28, 2021 at 9:41:01 AM UTC+8, Grant Taylor wrote:
> On 7/27/21 7:32 PM, hongy...@gmail.com wrote:
> > On server side:
> >
> > werner@X10DAi:~$ echo $DISPLAY
> > :1
> Did you run that from your SSH connection? Or directly on the server?

Directly on the server:
werner@X10DAi:~$ echo $DISPLAY
:1

From the SSH connection

werner@X10DAi:~$ echo $DISPLAY
localhost:10.0
> :1 /may/ be okay for a remote connection. But it may also be a
> reference to a local / physical display on the server.
> > On client side, it's empty:
> >
> > $ echo $DISPLAY
> I would have expected the client to have a DISPLAY variable set.
> ESPECIALLY if running it form in a GUI terminal emulator.
> > I run ssh in verbose mode (-v):
> Verbose mode shouldn't change the behavior of X11 forwarding. But it
> will give more information.
> > Then xterm also fails to open display, and it says that X11 connection
> > rejected because of wrong authentication.
> Okay. That's sort of what I was expecting.
>
> You can use the 'xhost' command to allow other clients to connect
> bypassing the ~/.Xauthority (?) cooky. E.g.
>
> xhost +192.0.2.1
>
> That should allow 192.0.2.1 to connect to your local X11 display.
>
> N.B. You can remove the IP and just use "+" to allow all IPs to connect
> too.

Thanks. I've run the `xhost +' on server side now:
werner@X10DAi:~$ xhost +
access control disabled, clients can connect from any host

> Use the following command to remove permission:
>
> xhost -
>
> N.B. My understanding is that the xhost permissions are non-persistent.
> > I've enabled the following options on server and client sides:
> That means that OpenSSH is configured to allow X11 forwarding.
>
> As Keith mentioned, the "-Y" option may help.

Now, I connect to the server with the following setting:

$ ssh -Y werner@192.168.10.100
The testing results:

Xterm works, but Emacs still report the same problem.

HY

On Wednesday, July 28, 2021 at 10:04:46 AM UTC+8, Keith Thompson wrote:
> "hongy...@gmail.com" <hongy...@gmail.com> writes:
> > On Wednesday, July 28, 2021 at 2:33:54 AM UTC+8, Grant Taylor wrote:
> >> On 7/27/21 7:30 AM, hongy...@gmail.com wrote:
> >> > Any hints for solving this problem?
> >> What is the DISPLAY environment variable set to?
> >
> > On server side:
> >
> > werner@X10DAi:~$ echo $DISPLAY
> > :1
> >
> > On client side, it's empty:
> >
> > $ echo $DISPLAY
> >
> > $
> That seems inconsistent with your original post. You said you got this
> message from emacs:
> Display localhost:10.0 unavailable, simulating -nw
> which strongly implies that $DISPLAY was set to "localhost:10.0", at
> least in your emacs process.
>
> Try `echo $DISPLAY` and `emacs` from the same shell process. If you get
> an empty string from the first (it's more likely that $DISPLAY is not
> set than that it's set to the empty string) and "Display localhost:10.0
> unavailable, simulating -nw" from emacs, then something very strange is
> going on.
>
> What does `env | grep '^DISPLAY='` print?

Sorry for my unclear description to some extent, especially on the network topology used by the testing in question. I restate the network topology below:

The ssh server: 192.168.10.100
The ssh client: 192.168.10.101

But the ssh client in my situation is a virtual machine running within Proxmox VE, so I must ssh into it first for doing the testing discussed here.

If I ssh to the client like the following:

$ ssh werner@192.168.10.101
$ env | grep '^DISPLAY='
$

If with the following option:

$ ssh -Y werner@192.168.10.101
$ env | grep '^DISPLAY='
DISPLAY=localhost:10.0

HY

On Tue, 27 Jul 2021 22:18:56 -0400, hongy...@gmail.com <hongyi.zhao@gmail.com> wrote:

> On Wednesday, July 28, 2021 at 10:04:46 AM UTC+8, Keith Thompson wrote:
>> "hongy...@gmail.com" <hongy...@gmail.com> writes:
>> > On Wednesday, July 28, 2021 at 2:33:54 AM UTC+8, Grant Taylor wrote:
>> >> On 7/27/21 7:30 AM, hongy...@gmail.com wrote:
>> >> > Any hints for solving this problem?
>> >> What is the DISPLAY environment variable set to?
>> >
>> > On server side:
>> >
>> > werner@X10DAi:~$ echo $DISPLAY
>> > :1
>> >
>> > On client side, it's empty:
>> >
>> > $ echo $DISPLAY
>> >
>> > $
>> That seems inconsistent with your original post. You said you got this
>> message from emacs:
>> Display localhost:10.0 unavailable, simulating -nw
>> which strongly implies that $DISPLAY was set to "localhost:10.0", at
>> least in your emacs process.
>>
>> Try `echo $DISPLAY` and `emacs` from the same shell process. If you get
>> an empty string from the first (it's more likely that $DISPLAY is not
>> set than that it's set to the empty string) and "Display localhost:10.0
>> unavailable, simulating -nw" from emacs, then something very strange is
>> going on.
>>
>> What does `env | grep '^DISPLAY='` print?
>
> Sorry for my unclear description to some extent, especially on the network topology used by the testing in question. I restate the network topology below:
>
> The ssh server: 192.168.10.100
> The ssh client: 192.168.10.101
>
> But the ssh client in my situation is a virtual machine running within Proxmox VE, so I must ssh into it first for doing the testing discussed here.
>
> If I ssh to the client like the following:
>
> $ ssh werner@192.168.10.101
> $ env | grep '^DISPLAY='
> $
>
> If with the following option:
>
> $ ssh -Y werner@192.168.10.101
> $ env | grep '^DISPLAY='
> DISPLAY=localhost:10.0

Got emacs to work in gui mode under ssh.

Try running "ssh -X -Y werner@192.168.10.101"
then running emacs.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

On Tue, 27 Jul 2021 22:18:56 -0400, hongy...@gmail.com <hongyi.zhao@gmail.com> wrote:
> Sorry for my unclear description to some extent, especially on the network topology used by the testing in question. I restate the network topology below:
>
> The ssh server: 192.168.10.100
> The ssh client: 192.168.10.101
>
> But the ssh client in my situation is a virtual machine running within Proxmox VE, so I must ssh into it first for doing the testing discussed here.
>
> If I ssh to the client like the following:
>
> $ ssh werner@192.168.10.101
> $ env | grep '^DISPLAY='
> $
>
> If with the following option:
>
> $ ssh -Y werner@192.168.10.101
> $ env | grep '^DISPLAY='
> DISPLAY=localhost:10.0

One point that is often misunderstood. When discussing X, the server is the one
that's physically connected to the monitor. The gui programs you run on the
system you're connecting to via ssh become clients of the X server running on
the machine you're connecting from.

I partially figure out how to get it working. After connecting via ssh to the
remote system, run "DISPLAY= emacs". It works, but runs emacs in text mode
instead of gui mode.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

On Tue, 27 Jul 2021 22:07:16 -0400, hongy...@gmail.com <hongyi.zhao@gmail.com> wrote:
> Xterm works, but Emacs still report the same problem.

In that case stop looking at X or ssh settings. It's a problem with emacs, not
the ssh or X setup.

The man page for emacs has a section for running it under X. It's not a program
I use or am familiar with.

If no one else here has an idea, please open a bug report for emacs. Perhaps
it's package maintainer will have an idea.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

On Wednesday, July 28, 2021 at 11:49:11 AM UTC+8, David W. Hodgins wrote:
> On Tue, 27 Jul 2021 22:18:56 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
>
> > On Wednesday, July 28, 2021 at 10:04:46 AM UTC+8, Keith Thompson wrote:
> >> "hongy...@gmail.com" <hongy...@gmail.com> writes:
> >> > On Wednesday, July 28, 2021 at 2:33:54 AM UTC+8, Grant Taylor wrote:
> >> >> On 7/27/21 7:30 AM, hongy...@gmail.com wrote:
> >> >> > Any hints for solving this problem?
> >> >> What is the DISPLAY environment variable set to?
> >> >
> >> > On server side:
> >> >
> >> > werner@X10DAi:~$ echo $DISPLAY
> >> > :1
> >> >
> >> > On client side, it's empty:
> >> >
> >> > $ echo $DISPLAY
> >> >
> >> > $
> >> That seems inconsistent with your original post. You said you got this
> >> message from emacs:
> >> Display localhost:10.0 unavailable, simulating -nw
> >> which strongly implies that $DISPLAY was set to "localhost:10.0", at
> >> least in your emacs process.
> >>
> >> Try `echo $DISPLAY` and `emacs` from the same shell process. If you get
> >> an empty string from the first (it's more likely that $DISPLAY is not
> >> set than that it's set to the empty string) and "Display localhost:10.0
> >> unavailable, simulating -nw" from emacs, then something very strange is
> >> going on.
> >>
> >> What does `env | grep '^DISPLAY='` print?
> >
> > Sorry for my unclear description to some extent, especially on the network topology used by the testing in question. I restate the network topology below:
> >
> > The ssh server: 192.168.10.100
> > The ssh client: 192.168.10.101
> >
> > But the ssh client in my situation is a virtual machine running within Proxmox VE, so I must ssh into it first for doing the testing discussed here.
> >
> > If I ssh to the client like the following:
> >
> > $ ssh wer...@192.168.10.101
> > $ env | grep '^DISPLAY='
> > $
> >
> > If with the following option:
> >
> > $ ssh -Y wer...@192.168.10.101
> > $ env | grep '^DISPLAY='
> > DISPLAY=localhost:10.0
> Got emacs to work in gui mode under ssh.
>
> Try running "ssh -X -Y wer...@192.168.10.101"
> then running emacs.

I tried the above from the server side itself:

$ ssh -XY werner@192.168.10.100

Then run emacs, but encounter the same message:

$ emacs
Display localhost:10.0 unavailable, simulating -nw

On Wednesday, July 28, 2021 at 11:49:12 AM UTC+8, David W. Hodgins wrote:
> On Tue, 27 Jul 2021 22:18:56 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
> > Sorry for my unclear description to some extent, especially on the network topology used by the testing in question. I restate the network topology below:
> >
> > The ssh server: 192.168.10.100
> > The ssh client: 192.168.10.101
> >
> > But the ssh client in my situation is a virtual machine running within Proxmox VE, so I must ssh into it first for doing the testing discussed here.
> >
> > If I ssh to the client like the following:
> >
> > $ ssh wer...@192.168.10.101
> > $ env | grep '^DISPLAY='
> > $
> >
> > If with the following option:
> >
> > $ ssh -Y wer...@192.168.10.101
> > $ env | grep '^DISPLAY='
> > DISPLAY=localhost:10.0
> One point that is often misunderstood. When discussing X, the server is the one
> that's physically connected to the monitor. The gui programs you run on the
> system you're connecting to via ssh become clients of the X server running on
> the machine you're connecting from.
>
> I partially figure out how to get it working. After connecting via ssh to the
> remote system, run "DISPLAY= emacs". It works, but runs emacs in text mode
> instead of gui mode.

I tried with your suggested method:
$ DISPLAY= emacs

But is seems that I still have the same result as before. To be clear, I want to have a pdf preview frame opened in Emacs with pdf-tools, which works smoothly when I locally use it on the machine.

HY

On Wed, 28 Jul 2021 00:12:54 -0400, hongy...@gmail.com <hongyi.zhao@gmail.com> wrote:
> I tried the above from the server side itself:
>
> $ ssh -XY werner@192.168.10.100
>
> Then run emacs, but encounter the same message:
>
> $ emacs
> Display localhost:10.0 unavailable, simulating -nw

Strange. Try ...
$ ssh -XY werner@192.168.10.100
$ DISPLAY=:0 emacs

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

On Wednesday, July 28, 2021 at 1:21:28 PM UTC+8, David W. Hodgins wrote:
> On Wed, 28 Jul 2021 00:12:54 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
> > I tried the above from the server side itself:
> >
> > $ ssh -XY wer...@192.168.10.100
> >
> > Then run emacs, but encounter the same message:
> >
> > $ emacs
> > Display localhost:10.0 unavailable, simulating -nw
> Strange. Try ...
> $ ssh -XY wer...@192.168.10.100
> $ DISPLAY=:0 emacs

werner@X10DAi:~$ DISPLAY=:0 emacs
No protocol specified
Display :0 unavailable, simulating -nw

HY

On Wed, 28 Jul 2021 01:25:04 -0400, hongy...@gmail.com <hongyi.zhao@gmail.com> wrote:

> On Wednesday, July 28, 2021 at 1:21:28 PM UTC+8, David W. Hodgins wrote:
>> On Wed, 28 Jul 2021 00:12:54 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
>> > I tried the above from the server side itself:
>> >
>> > $ ssh -XY wer...@192.168.10.100
>> >
>> > Then run emacs, but encounter the same message:
>> >
>> > $ emacs
>> > Display localhost:10.0 unavailable, simulating -nw
>> Strange. Try ...
>> $ ssh -XY wer...@192.168.10.100
>> $ DISPLAY=:0 emacs
>
> werner@X10DAi:~$ DISPLAY=:0 emacs
> No protocol specified
> Display :0 unavailable, simulating -nw

I'm out of ideas. I know it's working for me, so it's not a Mageia bug, just
something different about that setup. Hopefully someone else here will figure
it out.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

On Wednesday, July 28, 2021 at 1:51:23 PM UTC+8, David W. Hodgins wrote:
> On Wed, 28 Jul 2021 01:25:04 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
>
> > On Wednesday, July 28, 2021 at 1:21:28 PM UTC+8, David W. Hodgins wrote:
> >> On Wed, 28 Jul 2021 00:12:54 -0400, hongy...@gmail.com <hongy...@gmail..com> wrote:
> >> > I tried the above from the server side itself:
> >> >
> >> > $ ssh -XY wer...@192.168.10.100
> >> >
> >> > Then run emacs, but encounter the same message:
> >> >
> >> > $ emacs
> >> > Display localhost:10.0 unavailable, simulating -nw
> >> Strange. Try ...
> >> $ ssh -XY wer...@192.168.10.100
> >> $ DISPLAY=:0 emacs
> >
> > werner@X10DAi:~$ DISPLAY=:0 emacs
> > No protocol specified
> > Display :0 unavailable, simulating -nw
> I'm out of ideas. I know it's working for me, so it's not a Mageia bug, just
> something different about that setup. Hopefully someone else here will figure
> it out.

Got it. To be sure, your method is right, but I happened to use an error value of "$DISPLAY". Here, I summarize the successful methods as follows:

Obtain the value of `$DISPLAY' locally on the ssh server:

$ echo $DISPLAY
:1

Then all the following methods will do the trick:

Method 1:

$ ssh -X -f werner@192.168.10.100 DISPLAY=:1 emacs
or
$ ssh -X -f werner@192.168.10.100 env DISPLAY=:1 emacs

Method 2:

$ ssh -X werner@192.168.10.100

Then run any of the following commands:

$ DISPLAY=:1 emacs
$ env DISPLAY=:1 emacs
$ emacs -d :1
$ emacs --display :1

NB.

[1]. I obtain the clues from here: <https://kb.iu.edu/d/acxu>
[2]. X server relevant options supplied by Emacs:

werner@X10DAi:~$ man emacs|grep -A 4 -- '-d '
-d displayname, --display=displayname
Create the Emacs window on the display specified by dis‐
playname. Must be the first option specified in the com‐
mand line.

werner@X10DAi:~$ emacs --help|grep -- '-d '
--display, -d DISPLAY use X server DISPLAY

Regards,
HY

On Wednesday, July 28, 2021 at 3:02:38 PM UTC+8, hongy...@gmail.com wrote:
> On Wednesday, July 28, 2021 at 1:51:23 PM UTC+8, David W. Hodgins wrote:
> > On Wed, 28 Jul 2021 01:25:04 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
> >
> > > On Wednesday, July 28, 2021 at 1:21:28 PM UTC+8, David W. Hodgins wrote:
> > >> On Wed, 28 Jul 2021 00:12:54 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
> > >> > I tried the above from the server side itself:
> > >> >
> > >> > $ ssh -XY wer...@192.168.10.100
> > >> >
> > >> > Then run emacs, but encounter the same message:
> > >> >
> > >> > $ emacs
> > >> > Display localhost:10.0 unavailable, simulating -nw
> > >> Strange. Try ...
> > >> $ ssh -XY wer...@192.168.10.100
> > >> $ DISPLAY=:0 emacs
> > >
> > > werner@X10DAi:~$ DISPLAY=:0 emacs
> > > No protocol specified
> > > Display :0 unavailable, simulating -nw
> > I'm out of ideas. I know it's working for me, so it's not a Mageia bug, just
> > something different about that setup. Hopefully someone else here will figure
> > it out.
> Got it. To be sure, your method is right, but I happened to use an error value of "$DISPLAY". Here, I summarize the successful methods as follows:
>
> Obtain the value of `$DISPLAY' locally on the ssh server:
>
> $ echo $DISPLAY
> :1

Or use the following method:

$ xdpyinfo | grep -i display
name of display: :1

> Then all the following methods will do the trick:
>
> Method 1:
>
> $ ssh -X -f wer...@192.168.10.100 DISPLAY=:1 emacs
> or
> $ ssh -X -f wer...@192.168.10.100 env DISPLAY=:1 emacs
>
> Method 2:
>
> $ ssh -X wer...@192.168.10.100
>
> Then run any of the following commands:
>
> $ DISPLAY=:1 emacs
> $ env DISPLAY=:1 emacs
> $ emacs -d :1
> $ emacs --display :1
>
> NB.
>
> [1]. I obtain the clues from here: <https://kb.iu.edu/d/acxu>
> [2]. X server relevant options supplied by Emacs:
>
> werner@X10DAi:~$ man emacs|grep -A 4 -- '-d '
> -d displayname, --display=displayname
> Create the Emacs window on the display specified by dis‐
> playname. Must be the first option specified in the com‐
> mand line.
>
> werner@X10DAi:~$ emacs --help|grep -- '-d '
> --display, -d DISPLAY use X server DISPLAY
>
> Regards,
> HY

On Wednesday, July 28, 2021 at 3:36:18 PM UTC+8, hongy...@gmail.com wrote:
> On Wednesday, July 28, 2021 at 3:02:38 PM UTC+8, hongy...@gmail.com wrote:
> > On Wednesday, July 28, 2021 at 1:51:23 PM UTC+8, David W. Hodgins wrote:
> > > On Wed, 28 Jul 2021 01:25:04 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
> > >
> > > > On Wednesday, July 28, 2021 at 1:21:28 PM UTC+8, David W. Hodgins wrote:
> > > >> On Wed, 28 Jul 2021 00:12:54 -0400, hongy...@gmail.com <hongy...@gmail.com> wrote:
> > > >> > I tried the above from the server side itself:
> > > >> >
> > > >> > $ ssh -XY wer...@192.168.10.100
> > > >> >
> > > >> > Then run emacs, but encounter the same message:
> > > >> >
> > > >> > $ emacs
> > > >> > Display localhost:10.0 unavailable, simulating -nw
> > > >> Strange. Try ...
> > > >> $ ssh -XY wer...@192.168.10.100
> > > >> $ DISPLAY=:0 emacs
> > > >
> > > > werner@X10DAi:~$ DISPLAY=:0 emacs
> > > > No protocol specified
> > > > Display :0 unavailable, simulating -nw
> > > I'm out of ideas. I know it's working for me, so it's not a Mageia bug, just
> > > something different about that setup. Hopefully someone else here will figure
> > > it out.
> > Got it. To be sure, your method is right, but I happened to use an error value of "$DISPLAY". Here, I summarize the successful methods as follows:
> >
> > Obtain the value of `$DISPLAY' locally on the ssh server:
> >
> > $ echo $DISPLAY
> > :1
> Or use the following method:
>
> $ xdpyinfo | grep -i display
> name of display: :1

Another issue: how to obtain the correct value of the above variable from within the ssh client instead of locally logged into the machine?

HY

"hongy...@gmail.com" <hongyi.zhao@gmail.com> writes:
[...]
>> Got it. To be sure, your method is right, but I happened to use an
>> error value of "$DISPLAY". Here, I summarize the successful methods
>> as follows:
>>
>> Obtain the value of `$DISPLAY' locally on the ssh server:
>>
>> $ echo $DISPLAY
>> :1
>
> Or use the following method:
>
> $ xdpyinfo | grep -i display
> name of display: :1

That seems pointless. xdpyinfo gets the value to show by looking at
$DISPLAY. (I had suggested running xdpyinfo just to see whether it
succeeds or fails.)

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips
void Void(void) { Void(); } /* The recursive call of the void */

On Wednesday, July 28, 2021 at 10:24:45 PM UTC+8, Keith Thompson wrote:
> "hongy...@gmail.com" <hongy...@gmail.com> writes:
> [...]
> >> Got it. To be sure, your method is right, but I happened to use an
> >> error value of "$DISPLAY". Here, I summarize the successful methods
> >> as follows:
> >>
> >> Obtain the value of `$DISPLAY' locally on the ssh server:
> >>
> >> $ echo $DISPLAY
> >> :1
> >
> > Or use the following method:
> >
> > $ xdpyinfo | grep -i display
> > name of display: :1
> That seems pointless. xdpyinfo gets the value to show by looking at
> $DISPLAY. (I had suggested running xdpyinfo just to see whether it
> succeeds or fails.)

Then, where does $DISPLAY come from?

HY