Tunnel synergy KVM sharing software through SSH

Synergy is a popular KVM sharing software that allows you to control multiple hosts on the network with one keyboard and mouse. The software works well but is rediculously insecure, with all copied text and keyboard buffers being transmitted accross the network in unencrypted plaintext. This can lead to passwords and other sensitive information being sniffed or even malicious code execution.
Fortunately there is a simple fix that will vastly reduce the risk associated with using this software:
SSH Forwarding

On the server:
(the host with the keyboard and mouse you want to use)
Start the ssh service and the synergy server GUI in the normal way.

On the client:
Simply run:
ssh -l <username to connect to> <ip address of synergy server> -N -f -C -L 24800:localhost:24800

  • -l login name
  • -N do not execute a remote command
  • -f  background SSH session
  • -L port:host:hostport (local port, host and hostport are where you want the tunnel to point to.
  • -C compression – may improve performance

This should initiate the tunnel in the background, finally connect to the synergy server with:
synergyc -1 localhost

Thats it, you should now enjoy a well encrypted KVM connection between your hosts.