Resposta do suporte do BTsync
Sync has ability to configurate network settings such as port using configuration file. You can find more info regarding it here:
http://help.getsync.com/hc/en-us/articles/204762689
The option you are looking for is located in webui section
"listen" : <IP: port>
For example, 0.0.0.0:4444 will listen to any interface on the LAN at port 4444.
Portanto, especifique a porta para algo específico para evitar colisões.