Product: Synergy (all versions)
Operating system: Windows, macOS, and Linux
In a few rare cases when the cursor lags or gets randomly disconnected, we recommend using an ethernet connection instead of wifi, as it is usually faster, more secure, and more reliable. An ethernet connection will ensure further stability when using Synergy.
You will need an ethernet cable, and perhaps a USB ethernet adapter, as most modern laptops don't have an ethernet port. But if you're an Apple user, you can use a single thunderbolt 1 and 2 cable to form a network bridge between your computers. In this case, you won’t need an ethernet cable or switch; simply connect your two Macs together with a thunderbolt cable.
There are three options to set this up: connect to your existing router (the easiest option); set up a new switch; or use a crossover cable.
Option 1: Connect to your existing router
Your Internet router usually has a few spare ethernet ports on the back that you can plug straight into, and plug the other end of the cable in your computer. This requires only one regular ethernet cable.
If your router is in another room, you could run a cable between your living room and home office, but that's not always practical. An option is to have ethernet cables installed in all the walls, which is also not very practical. The best solution is to use Powerline Adapters; these will create an ethernet network out of the existing power circuit in your home.
Option 2: Set up a new switch
Purchase a new switch. You don’t need the fanciest and latest model; you just need one that works.
Connect both of your computers to the switch using a regular ethernet cable. After this, you will need to set up a static IP since you're not connected to your router (which usually takes care of IP).
To set up a static IP:
Windows: To set up a static IP varies between different versions of Windows, check out How-To Geek: How to Assign a Static IP Address in Windows 10 or Windows 11
macOS: Usually this is pretty simple to do on macOS and doesn't vary much between versions. This guide from Macinstruct tells you everything you need to know: How to Set a Static IP Address in Mac OS X.
Linux: This guide for Ubuntu users is helpful: Setting a static IP on Ubuntu: a beginner's guide.
Option 3: Use a Crossover Cable
1. You will need to connect the two computers together with a single cable, but if you're not using gigabit it will have to be a special crossover ethernet cable. The images below illustrate the difference between regular cables and crossover cables. You can buy these already made from all major retailers (e.g. Amazon).
2. As with using an isolated switch described above, you'll need to set up a static IP since you're not connected to your router. You can follow the same steps mentioned above.