Input Leap
Input Leap lets you easily share a single mouse and keyboard between multiple computers (even with different operating systems) without the need for special hardware. It is intended for users with multiple computers on their desk since each system uses its own monitor(s).
Redirecting the mouse and keyboard is as simple as moving the mouse off the edge of your screen. Input Leap also merges the clipboards of all the systems into one, allowing cut-and-paste between systems. Furthermore, it synchronizes screen savers so they all start and stop together and, if screen locking is enabled, only one screen requires a password to unlock them all.
When the work on Synergy stalled recently due to Symless (the company behind Synergy) halting further development of the 1.x branch and concentrating on 2.x branch, which is primarily closed-source, configured through a hosted web interface and requires a paid subscription. A fork called Barrier was created to continue development of the 1.x branch, containing many bug fixes and new features. After issues with that fork, active maintainers have created another fork called input-leap.
Installation
Input Leap
Install input-leapAUR package or input-leap-gitAUR.
Wayland support in Gnome or KDE 6.1+ which support the input capture portal.
Synergy or Barrier
You can install the synergyAUR or barrier package. There is also a synergy1-binAUR package which however does not include the synergys.service and synergys.socket systemd units.
Synergy 3
Around June of 2023, Symless released Synergy 3 which is paid software. To install the latest version there is a user package synergy3-binAUR, which currently out of date and possibly needs a new maintainer.
Once installed, run the GUI to setup your configuration. Then enable/start the synergy.service user unit.
Now Synergy will run without the GUI based on the configuration you setup. You can have the GUI open and the service will work along with it.
Windows and macOS
Download and run the newest Synergy installer from the official website. The official version is paid, although you may compile and run your own builds for free using sources on GitHub. You can also install Barrier for free instead.
Unfortunately, you will have to compile Input Leap yourself. They have provided instructions for Windows and macOS.
Pre-configuration
First determine the IP addresses and host names for each machine and make sure each has a correct hosts file. (You may use IP addresses instead of hostnames as well.)
- Arch Linux -
/etc/hosts - Windows -
C:\WINDOWS\system32\drivers\etc\hosts - macOS - How to Add Hosts to Local Hosts File[dead link 2023-07-30 ⓘ].
/etc/hosts
10.10.66.1 archserver.localdomain archserver 10.10.66.100 archleft.localdomain archleft 10.10.66.105 archright.localdomain archright
Server configuration
In Synergy, the computer with keyboard and mouse you want to share is called the server. See Synergy Configuration File Format for a detailed description of all available sections and options.
Arch Linux
Synergy stores its configuration under /etc/synergy.conf, Barrier uses /etc/barrier.conf or $HOME/.local/share/barrier/.barrier.conf. If the configuration file does not exist, you can use the provided GUI (started with $ synergy or $ barrier, or the desktop launcher) to create it visually. Alternatively you may create it by copying /etc/synergy.conf.example or /usr/share/doc/barrier-headless/barrier.conf.example, whose comments should give you enough information for a basic configuration; if you need further reference or would like to use more advanced options not available from the GUI, read the guide mentioned above.
If you experience problems and you wish to run the server in the foreground, you can run the following command instead:
# synergys -f
The synergy server process needs to attach to your user's X session, which means it needs to run as your user. Enable the synergys.service user unit.
synergys.socket to start the server when a client tries to connect instead. This is useful when the service cannot connect to an X server on boot.Set up encryption on server
To generate a certificate and fingerprint for the server to use.
For Barrier:
Note: Barrier v2.4.0 introduced a new keyfile format, which requires a SHA256 fingerprint and "v2:sha256:$fingerprint" formatted lines. For older versions, make sure the fingerprints are SHA1 and do not include a prefix.
$ mkdir -p ~/.local/share/barrier/SSL/Fingerprints; $ openssl req -x509 -nodes -days 365 -subj /CN=Barrier -newkey rsa:4096 -keyout ~/.local/share/barrier/SSL/Barrier.pem -out ~/.local/share/barrier/SSL/Barrier.pem; $ fingerprint=$(openssl x509 -fingerprint -sha256 -noout -in ~/.local/share/barrier/SSL/Barrier.pem | cut -d"=" -f2); $ echo "v2:sha256:$fingerprint" > ~/.local/share/barrier/SSL/Fingerprints/Local.txt;
For Synergy:
$ mkdir -p ~/.synergy/SSL/Fingerprints; $ openssl req -x509 -nodes -days 365 -subj /CN=Synergy -newkey rsa:4096 -keyout ~/.synergy/SSL/Synergy.pem -out ~/.synergy/SSL/Synergy.pem; $ fingerprint=$(openssl x509 -fingerprint -sha1 -noout -in ~/.synergy/SSL/Synergy.pem | cut -d"=" -f2); $ echo "$fingerprint" > ~/.synergy/SSL/Fingerprints/Local.txt;
To activate the SSL plugin, add the --enable-crypto option. (Note that the Synergy GUI will not let you enable encryption without a valid license, whereas the Barrier GUI allows doing so.)
- Starting from the command line:
$ synergys --enable-crypto
Windows
- Open the Synergy program
- Select the option Server (share this computer's mouse and keyboard)
- Select Configure interactively
- Click the Configure Server... button
- This opens a window in which you can add screens depending on how many computers/screens you have: just drag the screen icon in the top-right corner to the screens area, and double-click it to edit its settings
- Click OK to close the screens window when you are ready, then click on Start to start the server
On Windows, configuration is saved by default in a synergy.sgc file, but its name and location can of course be changed at pleasure.
If you want to start the Synergy server everytime Windows starts, you have to launch the program as administrator, then go to Edit -> Services and select Install in the Server section; note that at the following reboot Synergy will indeed automatically start, but the tray icon will not display automatically (at least for version 1.4.2 beta on Windows 7). To uninstall the service, do the same thing but obviously select Uninstall.
If you want to start the server from the command-line, here is a Windows command you can place in a .bat file or just run from cmd.exe:
C:\Program Files\Synergy+\bin\synergys.exe -f --debug ERROR --name left --log c:\windows\synergy.log -c C:/windows/synergy.sgc --address 10.66.66.2:24800
macOS
macOS has a similar configuration as Unix: check the official documentation for more information.
Configuration examples
This is an example for a basic 3-computers setup:
/etc/synergy.conf
section: screens server-fire: archright-fire: archleft-fire: end section: links archleft-fire: right = server-fire server-fire: right = archright-fire left = archleft-fire archright-fire: left = server-fire end
This should be the example bundled with the Arch Linux package:
/etc/synergy.conf
section: screens
# three hosts named: moe, larry, and curly
moe:
larry:
curly:
end
section: links
# larry is to the right of moe and curly is above moe
moe:
right = larry
up = curly
# moe is to the left of larry and curly is above larry.
# note that curly is above both moe and larry and moe
# and larry have a symmetric connection (they're in
# opposite directions of each other).
larry:
left = moe
up = curly
# larry is below curly. if you move up from moe and then
# down, you'll end up on larry.
curly:
down = larry
end
section: aliases
# curly is also known as shemp
curly:
shemp
end
The following is a more customized example:
synergy.sgc
section: screens leftpc: halfDuplexCapsLock = false halfDuplexNumLock = false halfDuplexScrollLock = false xtestIsXineramaUnaware = false switchCorners = none +top-left +top-right +bottom-left +bottom-right switchCornerSize = 0 rightpc: halfDuplexCapsLock = false halfDuplexNumLock = false halfDuplexScrollLock = false xtestIsXineramaUnaware = false switchCorners = none +top-left +top-right +bottom-left +bottom-right switchCornerSize = 0 end section: aliases leftpc: 10.66.66.2 rightpc: 10.66.66.1 end section: links leftpc: right = rightpc rightpc: left = leftpc end section: options heartbeat = 1000 relativeMouseMoves = false screenSaverSync = false win32KeepForeground = false switchCorners = none +top-left +top-right +bottom-left +bottom-right switchCornerSize = 4 end
Clients configuration
Arch Linux
In a console window, type:
$ synergyc server-host-name
Or, to run synergy in the foreground:
$ synergyc -f server-host-name
Here, server-host-name is the host name of the server.
Set up encryption on client
If you use the synergy command line client, copy the file containing the fingerprint ~/.synergy/SSL/Fingerprints/Local.txt from the server into the clients home directory ~/.synergy/SSL/Fingerprints/TrustedServers.txt. To start the synergy command line client with encryption, type:
$ synergyc --enable-crypto server-host-name
If you want to enable the SSL trust without requiring the GUI on the client you can follow the steps below, but you should confirm the fingerprint that gets displays is the same one your server has in its GUI or in the ~/.synergy/SSL/Fingerprints/Local.txt on the server per above. The echo -n is required to avoid the openssl client hanging waiting for input.
For Barrier:
Note: Barrier v2.4.0 introduced a new keyfile format, which requires a SHA256 fingerprint and a "v2:sha256:$fingerprint" line format. For older versions, make sure the fingerprints are SHA1 and do not include a prefix.
$ mkdir -p ~/.synergy/SSL/Fingerprints $ fingerprint=$(echo -n | openssl s_client -connect $YOUR_SYNERGY_SERVER:24800 2>/dev/null | openssl x509 -sha256 -noout -fingerprint | cut -d"=" -f2); $ echo "v2:sha256:$fingerprint" > ~/.synergy/SSL/Fingerprints/TrustedServers.txt
For Synergy:
$ mkdir -p ~/.synergy/SSL/Fingerprints $ fingerprint=$(echo -n | openssl s_client -connect $YOUR_SYNERGY_SERVER:24800 2>/dev/null | openssl x509 -sha1 -noout -fingerprint | cut -d"=" -f2); $ echo "$fingerprint" > ~/.synergy/SSL/Fingerprints/TrustedServers.txt
~/.local/share/synergy/SSL/Fingerprints/TrustedServers.txt, use this location if the one mentioned above does not work.Autostart
There exist several ways to automatically start the Synergy client, and they are actually the same that can be used for every other application.
server-host-name with the real server host name.- You can add the next line to your xinitrc:
~/.xinitrc
... #replace server-host-name with the real name synergyc server-host-name
The following is an alternative:
~/.xinitrc
XINIT_CMD='/usr/bin/synergyc -d FATAL -n galileo-fire 10.66.66.2:24800' /usr/bin/pgrep -lxf "$XINIT_CMD" || ( ( $XINIT_CMD ) & )
- Otherwise, if you are using a display manager (GDM, SDDM, ...), or a stand-alone window manager (Openbox, ...), you could exploit its start-up script and add the following:
synergyc server-host-name
- To start the Synergy client with systemd, create a service file:
~/.config/systemd/user/synergyc.service
[Unit] Description=Synergy Client Daemon After=network.target [Service] ExecStart=/usr/bin/synergyc --no-daemon server-name Restart=always RestartSec=3 [Install] WantedBy=default.target
Then do a daemon-reload and start the synergyc.service user unit.
To start the service at login for your user, enable it as a user unit.
Automatically starting Synergy is also documented in its official reference page.
Windows
After installation, open the Synergy program, select the option Client (use another computer's keyboard and mouse) and type the host name of the server computer in the text box, then click Start to start the client.
If you want to start the Synergy client every time Windows starts, you have to launch the program as an administrator, then go to Edit -> Services and select Install in the Client section.
If you want to start the client from the command-line, here is a Windows command you can place in a .bat file or just run from cmd.exe. This points to a configuration file in C:\synergy.sgc and runs in the background like a service.
START /MIN /D"C:\Program Files\Synergy+\bin" synergys.exe -d ERROR -n m6300 -c C:\synergy.sgc -a 10.66.66.2:24800
macOS
Locate the synergyc program in the synergyc folder and drag it onto the terminal window: the full path will appear in the terminal. Now append the host name of the server, so that the complete command will look like this:
/path/to/synergyc/synergyc server-host-name
Then press Enter.
Known issues
If Arch is being used as a client in a Synergy installation, the server may not be able to wake the client monitor. There are some workarounds, such as executing the following via SSH, if ACPI is enabled (see: Display Power Management Signaling#Runtime settings):
# xset dpms force on
Troubleshooting
The official documentation has a FAQ and also a troubleshooting page.
Keyboard AltGr
If you encounter problems with AltGr, add
altgr = alt #1.8.2 altgr = shift #v1.8.3 and higher
on the screen/client section in /etc/synergys.conf.
Keyboard repeat
If you experience problems with your keyboard repeat on the client machine (Linux host), simply type:
# /usr/bin/xset r on
in any console.
Keyboard mapping
If you experience problems with the keyboard mapping when using the server's keyboard in a client window (e.g a terminal) then re-setting the X key map after starting synergyc may help. The following command sets the keymap to its current value:
# setxkbmap $(setxkbmap -query | grep "^layout:" | awk -F ": *" '{print $2}')
No cursor in Gnome
When GNOME does not detect a mouse, it will default to touchscreen mode and hide the cursor. To enable run:
# dconf write /org/gnome/settings-daemon/plugins/cursor/active false
This can be added to an init script or systemd unit:
ExecStartPost=dconf write /org/gnome/settings-daemon/plugins/cursor/active false
Mixing xorg and wayland environments also does not currently work. Try starting gnome in xorg for both client and server.
Client is returning "failed to verify server certificate fingerprint"
You need to copy the content of server's ~/.synergy/SSL/Fingerprints/Local.txt into client's ~/.synergy/SSL/Fingerprints/TrustedServers.txt. See #Set up encryption on client.
Scroll Lock LED does not light
When using Scroll Lock to lock to a client (or to enter relative mouse move mode), you may run into an issue with your keyboard's Scroll Lock LED not lighting. This can be solved by binding the Scroll_Lock key to an empty modifier key.
First, find an empty modifier. In this case, mod3 is available:
$ xmodmap
xmodmap: up to 4 keys per modifier, (keycodes in parentheses): shift Shift_L (0x32), Shift_R (0x3e) lock Caps_Lock (0x42) control Control_L (0x25), Control_R (0x69) mod1 Alt_L (0x40), Alt_R (0x6c), Meta_L (0xcd) mod2 Num_Lock (0x4d) mod3 mod4 Super_L (0x85), Super_R (0x86), Super_L (0xce), Hyper_L (0xcf) mod5 ISO_Level3_Shift (0x5c), Mode_switch (0xcb)
Then, add the new mapping.
$ xmodmap -e 'add mod3 = Scroll_Lock' $ "echo "add mod3 = Scroll_Lock" >> ~/.Xmodmap
See Xmodmap#Activating the custom table to have ~/.Xmodmap loaded on login.
After making this change, test the LED and screen locking. If you find that you need to press Scroll Lock twice to lock screens, enable halfDuplexScrollLock on all screens in section: screens.
Additional mouse buttons do not work in client
If you find that additional mouse buttons (i.e. Mouse4/Mouse5) do not translate to a client, try adding the following to section: options:
mousebutton(6) = mousebutton(4) mousebutton(7) = mousebutton(5)
This will re-map the mouse keys to the proper number. If that does not fix the problem, remove the configuration, stop Synergy, and start it in the foreground with debug logging enabled:
$ synergys -f -d DEBUG1
Then, move your cursor to the screen of the client with the issue. Click the non-functioning keys, and watch for log entries like this:
[2017-09-30T14:56:45] DEBUG1: onMouseDown id=6 ... [2017-09-30T14:56:46] DEBUG1: onMouseUp id=6
The id=... part will have the right number to use in mousebutton(...)
Mouse fixed in certain games
In some applications (like Overwatch or other games) the cursor gets trapped in the middle of the screen.
According to https://github.com/symless/synergy-core/issues/2631 this is an issue that is known.
Just set relative mouse movement in your settings and make sure to lock the screen.
External links
- Synergy website: https://symless.com/synergy/
- Official documentation: https://github.com/symless/synergy-core/wiki/User-Guide