Hi, I'm using BtSync to sync my android smartphone, my Ubuntu laptop and a Ubuntu backup server. The android phone and the laptop are behind a very restrictive firewall and can't sync with the Ubuntu backup server, and I'm looking for a solution. Here is a schema : What can I do to try pass this firewall, how can I test the port (to try to find one working) or have I to give up ? With my laptop, I can reach the server with FTP, SSH, HTTP... Dropbox is working through this firewall. Thanks ! Ron