Litchi Magic Leash + Sprint

[cdenley]

Has anyone ever tried using the Litchi Magic Leash app over the Sprint network? Or anyone familiar with how that app connects (IP/port)?

I tried using it for the first time today. It works until the phone loses WiFi. But it shouldn't need WiFi, it should work over 4G. But if I disconnect from WiFi, it no longer connects. My Verizon device will connect without WiFi, but that is what I use with the drone controller.

UPDATE:
It looks like when it is working, it connects to TCP/45678 on 104.248.208.243. But the Sprint device (another app) can connect to that address without WiFi while Litchi Magic Leash still spins forever without asking for a pin. So either Sprint blocks another intermediate address that redirects somewhere else (104.248.208.243) based on geographic location, or something is messed up between the phone and app.

 

[cdenley]

As far as I can tell, the Litchi Magic Leash app does not support IPV6. Sprint does not assign IPV4 addresses, but that does not prevent apps from connecting to IPV4 servers. That is why other apps can connect fine over 4G. The Litchi Magic Leash app will apparently not work unless your Android device is assigned an IPV4 address though.

 

[cdenley]

So I setup my laptop as a WiFi hotspot to capture the network traffic to/from the Litchi Magic Leash app. I was surprised that at first, even while using WiFi, the Sprint phone still wouldn't connect. However, my Verizon phone would. But after uninstalling/reinstalling Litchi Magic Leash, it began working again. The network packet capture looked the same as with Verizon. A standard DNS A query for flylitchi.com, then a TCP connection on port 45678 with that address.

So I disconnect WiFi, then try to uninstall/reinstall Litch Magic Leash hoping it will magically start working on 4G like it did with WiFi. No luck.

I install PCAP Remote so I can see if the app is generating any network traffic while using 4G. This app does a non-root packet capture by creating a fake VPN interface it can capture traffic on, then routing all internet traffic through that interface as if it were a real VPN. While that fake VPN was configured, Litchi Magic Leash connected without issue!

So I guess I kind of have a workaround, but using a fake VPN and performing a packet capture every time I want to use this app is far from ideal. I tried using DNS Changer, which works similarly, but Litchi Magic Leash will not connect.

I tried multiple network utility apps, and none of them seem to have an issue connecting to flylitchi.com:45678 over any network. The Litchi Magic Leash app is the only app that fails to connect to its own server. There are no settings on the phone that would be blocking it (background data, power saving, mobile data, etc).

Anyone have any ideas? Is it the phone or the Sprint network? Any way for me to tell? Does Litchi offer any support?

 

[cdenley]

I enlisted the help of my soon-to-be mother-in-law to troubleshoot. 3 Sprint phones now, all are the same. Litchi Magic Leash will connect and prompt for a pin over WiFi, but disconnect WiFi and it will spin forever without prompting for a pin. Clearly there is either a bug with the app, or an issue with Sprint's network. But since other apps can connect (a TCP connection is a TCP connection), I don't think it is a network issue.

 

[cdenley]

I was able to work with Litchi troubleshooting the issue, and I have a version working on the Sprint phone. It seems to be related to how it converts the IPV4 their hostname resolves to into an IPV6 address. Hopefully a fix goes to the Android Play Market.

 

[Aaron24]

I was able to work with Litchi troubleshooting the issue, and I have a version working on the Sprint phone. It seems to be related to how it converts the IPV4 their hostname resolves to into an IPV6 address. Hopefully a fix goes to the Android Play Market.

Sorry to hijack your threat but does anyone know if this Litchi Magic Leash app will work with Mavic 2 drones? The app description on iOS does not mention Mavic 2, only Phantom 3 and 4 and Inspire aircraft.