Just to tighten up on this a little more. It would seem that on both Windows and Mac the device-to-device communication occurs on ports 24800 and 24810 which is used by the synergyd, synergys and synergyc processes. Port 24888 is also used but it appears just for local loop back purposes. Synergy2 (the GUI) just appears to use https to connect to Symless and also the local loop back. synergyd also makes an external connection to Symless on port 8081.