Firewall, use outside of home network, HELP

[ocphx 0]

At wits end trying to get Synergy_v2.0.3-stable_b1323-8a08e664-x64 to work between my Win 10 x64 laptop and my LinuxMint 18.3 x64 Cinnamon machine.  I waited until 2.0.3 to get Synergy to work on v2, but now the only way I can access the Linux machine and vice versa is to disable the firewall in Linux.  This seems like a ridiculous solution.  I posed this question to the Symless tech support, and have been receiving daily emails stating that they are inundated with support tickets.  I logged my first one on Nov. 27, 2017.  It's now Dec. 15, and I am still not using Synergy v2, which I purchased on 11/27. 

So I am hoping someone here can answer the following:

1. What configurations/rules do I have to enable or allow on the Linux firewall for Synergy to work?
2. Will I be able to use this outside of my home network, or am I bound to my home network?
3. Is there any functionality to be able to use the Linux machine (computer 2) as headless, meaning the screen would be displayed on Computer 1 when controlled, like Windows RDP?
4. What keyboard shortcut releases the control from one to the other?

Thanks in advance for your help!

[Michael_R 2]

These are the ports that I had to configure on the Linux firewall to get Synergy2 working

24888/tcp
24800-24802/tcp