KVM switch via software with Barrier

How to configure a KVM switch via software to share keyboard and mouse among multiple computers on the same local network.

KVM switch

A KVM switch (with KVM being an abbreviation for “keyboard, video, and mouse”) is a hardware device that allows a user to control multiple computers from one or more sets of keyboards, video monitors, and mice. Source: https://en.wikipedia.org/wiki/KVM_switch

Barrier

Barrier is software that mimics the functionality of a KVM switch allowing to use a single keyboard and mouse to control multiple computers by moving the mouse to the edge of the screen, or by using a keypress to switch focus to a different system. Source: https://github.com/debauchee/barrier

Setup Barrier server

Run Barrier GUI to create the config file.

Config file is saved at $HOME/.local/share/barrier/.barrier.conf, see below the config content for the settings made on the screenshots above.

section: screens
	maelcum:
		halfDuplexCapsLock = false
		halfDuplexNumLock = false
		halfDuplexScrollLock = false
		xtestIsXineramaUnaware = false
		preserveFocus = false
		switchCorners = none 
		switchCornerSize = 0
	lisis-joenio-dell:
		halfDuplexCapsLock = false
		halfDuplexNumLock = false
		halfDuplexScrollLock = false
		xtestIsXineramaUnaware = false
		preserveFocus = true
		switchCorners = none 
		switchCornerSize = 0
end

section: aliases
end

section: links
	maelcum:
		down = lisis-joenio-dell
	lisis-joenio-dell:
		up = maelcum
end

section: options
	relativeMouseMoves = false
	screenSaverSync = true
	win32KeepForeground = false
	clipboardSharing = true
	switchCorners = none 
	switchCornerSize = 0
end

Close the Barrier GUI and run Barrier server by command line, it will read the config file saved by the GUI.

$ barriers --no-daemon --no-tray --disable-crypto --disable-client-cert-checking
started server (IPv4), waiting for clients

Barrier client

$ barrierc --no-daemon 192.168.0.17
[2022-11-17T13:36:21] NOTE: started client
[2022-11-17T13:36:21] NOTE: connecting to '192.168.0.17': 192.168.0.17:24800
connected to server

Expected server output when the client connects successfully.

started server (IPv4), waiting for clients
[2022-11-17T13:36:21] NOTE: accepted client connection
[2022-11-17T13:36:21] NOTE: client "lisis-joenio-dell" has connected

Demo video