Difference between revisions of "Talk:KVM Alternatives for Linux"

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(Created page with "== this method is crap and does not work == What if you want to be able to COPY and PASTE between the two systems? Well use a different method to connect. On the SLAVE compu...")
 
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This article is wrong:
 
This article is wrong:
 
* https://www.linuxjournal.com/content/share-keyboardmouse-between-multiple-computers-x2x
 
* https://www.linuxjournal.com/content/share-keyboardmouse-between-multiple-computers-x2x
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== x2x doesn't have a very good manual page. ==
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 +
The problem you have with it being stuck on one-line is that the Xorg vertical Y axis increases going down. So your command line would be
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-completeregionup 0 -completeregionlow 1080
 +
 +
The -geometry argument is only to be used if you don't use north, south, east or west. It pops up a X window which, when you click in it, will activate the mouse and keyboard on the "to" desktop. To leave that desktop, you have to press two mouse buttons whilst over the x2x X window on the "from" desktop. (The mouse still moves over your home "from" desktop whilst in the remote "to" desktop.)
 +
 +
It's a good idea to use it once with the window, because it helps to understand how x2x works: it scales your own "from" desktop and projects it onto the "to" desktop. So, if you have two displays that aren't the same resolution, you will get a dead zone on "to" desktop. For me, I have a 1280x1024 on the left, and a 1366x768 on the right and they are aligned on their bottom edges. When this is projected onto the remote "to" desktop (originally a 1440x900), it left a block in the top-right corner that the mouse couldn't reach.
 +
 +
I've tried to work around this with the completeregion switches and got nowhere.
 +
 +
I found that if I managed to match my "to" desktop resolution with one of my from desktops and used the "-noscale" feature. I managed to get access to the whole "to" desktop. So I switched the remote down to 1280x1024 and used -noscale with -east and got a good layout.
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So I run this on my work "from" desktop with the two monitors.
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x2x -noscale -to my-remote:0.0 -east
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(Of course, you've managed to enable the TCP and managed the access control. Another couple of gotchas that could be mentioned in the manual page.)
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== xserver-allow-tcp=true ==
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You can run x2x over SSH, which is easy and secure, or connect x2x directly to the remote X server.
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the machines that run x2x have to support the XTEST X Window extension. Most Linux distributions do
 +
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If you are using a login manager such as gdm, you must enable remote TCP connections to the X server. In Ubuntu 8.04.1 run the command sudo /usr/sbin/gdmsetup. Select the Security tab and uncheck the “Deny TCP connections to the Xserver” checkbox.
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A quick check of netstat -a | grep x11 will tell you if you need to investigate further. If the result comes back containing LISTEN, you should be ready to go.
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* https://www.linux.com/news/x2x-software-alternative-kvm-switch/
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removed "-nolisten tcp" from /etc/X11/xinit/xserverrc
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/etc/gdm/custom.conf
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[security]
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DisallowTCP=false
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Create a new file /etc/gdm/custom.conf with this content:
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Code:
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[security]
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DisallowTCP=false
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Then reboot.
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# /etc/gdm/custom.conf
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[xdmcp]
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[chooser]
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[security]
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DisallowTCP=false
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[debug]
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Take care with letter case: it won't work
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 +
After that, all that is needed is a restart of the gdm process:
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sudo service gdm restart
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 +
You can verify the success as:
 +
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tzot@tzot-laptop:/etc/X11
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netstat -an | grep -F 6000
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 +
After an upgrade to 12.04, I had the same issue. This time, the culprit is the lightdm that the system uses. The file that needs to be updated is /etc/lightdm/lightdm.conf and the required addition is a xserver-allow-tcp=true in the [SeatDefaults] section.
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== kill host security, live on the edge ==
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vi /etc/ssh_config
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Host hostname
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    StrictHostKeyChecking no
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    UserKnownHostsFile /dev/null
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== internal link create ==
 +
 +
* [[X Windows to X Windows]]

Latest revision as of 22:03, 22 July 2020

this method is crap and does not work

What if you want to be able to COPY and PASTE between the two systems? Well use a different method to connect. On the SLAVE computer you need to execute this command: 

xhost 192.168.x.x

Where the IP address of the MASTER system is after xhost. You will get an exit status confirmation: 

192.168.x.x being added to access control list

On the MASTER computer type: 

x2x -to 192.168.x.x:0.0 -east

Where the IP address of the SLAVE system is specified

If you get "x2x - error: can not open display" then...

This article is wrong:

x2x doesn't have a very good manual page.

The problem you have with it being stuck on one-line is that the Xorg vertical Y axis increases going down. So your command line would be

-completeregionup 0 -completeregionlow 1080

The -geometry argument is only to be used if you don't use north, south, east or west. It pops up a X window which, when you click in it, will activate the mouse and keyboard on the "to" desktop. To leave that desktop, you have to press two mouse buttons whilst over the x2x X window on the "from" desktop. (The mouse still moves over your home "from" desktop whilst in the remote "to" desktop.)

It's a good idea to use it once with the window, because it helps to understand how x2x works: it scales your own "from" desktop and projects it onto the "to" desktop. So, if you have two displays that aren't the same resolution, you will get a dead zone on "to" desktop. For me, I have a 1280x1024 on the left, and a 1366x768 on the right and they are aligned on their bottom edges. When this is projected onto the remote "to" desktop (originally a 1440x900), it left a block in the top-right corner that the mouse couldn't reach.

I've tried to work around this with the completeregion switches and got nowhere.

I found that if I managed to match my "to" desktop resolution with one of my from desktops and used the "-noscale" feature. I managed to get access to the whole "to" desktop. So I switched the remote down to 1280x1024 and used -noscale with -east and got a good layout.

So I run this on my work "from" desktop with the two monitors.

x2x -noscale -to my-remote:0.0 -east

(Of course, you've managed to enable the TCP and managed the access control. Another couple of gotchas that could be mentioned in the manual page.)

xserver-allow-tcp=true

You can run x2x over SSH, which is easy and secure, or connect x2x directly to the remote X server.

the machines that run x2x have to support the XTEST X Window extension. Most Linux distributions do 

If you are using a login manager such as gdm, you must enable remote TCP connections to the X server. In Ubuntu 8.04.1 run the command sudo /usr/sbin/gdmsetup. Select the Security tab and uncheck the “Deny TCP connections to the Xserver” checkbox.

A quick check of netstat -a | grep x11 will tell you if you need to investigate further. If the result comes back containing LISTEN, you should be ready to go.

removed "-nolisten tcp" from /etc/X11/xinit/xserverrc


/etc/gdm/custom.conf

[security] DisallowTCP=false



Create a new file /etc/gdm/custom.conf with this content: Code:

[security] DisallowTCP=false

Then reboot.


  1. /etc/gdm/custom.conf

[xdmcp]

[chooser]

[security] DisallowTCP=false

[debug]

Take care with letter case: it won't work

After that, all that is needed is a restart of the gdm process:

sudo service gdm restart

You can verify the success as:

tzot@tzot-laptop:/etc/X11

netstat -an | grep -F 6000

After an upgrade to 12.04, I had the same issue. This time, the culprit is the lightdm that the system uses. The file that needs to be updated is /etc/lightdm/lightdm.conf and the required addition is a xserver-allow-tcp=true in the [SeatDefaults] section.

kill host security, live on the edge

vi /etc/ssh_config

Host hostname
    StrictHostKeyChecking no
    UserKnownHostsFile /dev/null

internal link create

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