Can I run the server to accept connection only inside my home local network?
Yes you can. On the settings dialog of the server, you can just type in the local IP address of your computer (something like 192.168.0.xxx), and do not click on the button of auto-detection of router’s external IP address and setup port forwarding. Then on your iPhone side, when your add a new server, type in your computer’s local IP address. To get your computer local IP address, bring up a command prompt window, and type in “ipconfig”.