Synergy is a well known tool to have only one keyboard and mouse for two networked (TCP/IP) computers with a screen each. I loved to use it at my former job. Now, at my new job, I've still got two PC, but they are in completely different and isolated networks: Administrative and development, Windows and Linux, accordingly.

Seeing a "serial" feature of putty (Windows), which usually is able to do all sorts of tunneling, I wonder whether it would allow me to use Synergy through a TCP-over-Serial connection. I reckon I'd need to use SLIP on the Linux side.

Has anyone got experience with this, or with parts of this?

  • 1
    I've been looking at making a hardware synergy assist. would anyone be interested ? May 18, 2009 at 22:31

3 Answers 3


If you're running SLIP (or, better, PPP), then you've built an IP network over your serial cable. You assign IP addresses (RFC 1918 private addresses most likely) on both sides, and use Synergy with those addresses. There wouldn't be any reason to use PuTTY's port forwarding.

Of course, your two networks are no longer isolated. Especially if you keep routing/forwarding turned off on both machines this may be OK or may not be, depending on your security policies and needs.


Do these machines have to be isolated? What about adding secondary NICs to both machines and then putting them both on a private network (10.10.1.x). Make sure that no traffic is routed through that network.

Another simpler option might just be to purchase a KVM and just use it for K&M.

  • uhm. that is a fairly good answer. Yes, those networks have to be isolated, and I reckon that a second NIC is therefore not acceptable, but not worse than what I asked for. I think I need either to rethink my request, or firewall it properly :) (KVM)-V is the current solution, and rather disappointing.
    – lImbus
    May 19, 2009 at 23:15
  • I'm curious what the problem with the KVM-V is? Is it that you have to hit a button on the KVM to switch? Or do you want to have the clipboard switch between machines? Many KVMs have keyboard shortcuts, this would be equivalent to moving the mouse from one screen to the other through Synergy.
    – GreenKiwi
    May 20, 2009 at 4:12
  • it's the clipboard, and it's the beep and time it takes for the (wireless) keyboard/mouse to be back responsive. I may have a cheap KVM, tho. Synergy was so much more intuitive since moving the mouse to where you were looking was sufficient. Now I bump on the screens edge, need to double-ctrl (baaaad baad fact it's on ctrl) and have to relocate the mouse on the other screen.
    – lImbus
    May 20, 2009 at 16:38
  • What about some device like this: microcenter.com/single_product_results.phtml?product_id=0194575 It's effectively the same as using slip over serial. As for KVMs, the slow change is very frustrating. I have found some KVMs that emulate the connection to the computer, i.e. the computer always thinks that a mouse+keyboard are connected. Then switching is almost instantaneous.
    – GreenKiwi
    May 20, 2009 at 16:58
  • @limbus: Check your KVM manual. Mine let me remap it to Scroll Lock x2. Jun 26, 2009 at 17:57

Here is synergy-through-usb https://github.com/iHateInventNames/synergy-through-usb

It allows to use usb2usb cable.

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