Ubuntu 20.04.02 | csf: v14.05
How to reproduce:
I have installed csf on two lan machines and i added both machines IPS to each csfs eg: csf -a 192.168.xx.xxx
(simple example, no installation)
Apps 1: LAN-Share and download appimage and save on both devices
https://github.com/abdularis/LAN-Share/releases (continues build)
Then run the app on both devices --> tap send --> send files --> choose a file --> now receivers must appear on the next window but no one
and you can do the same using another device app but no receiver appear.
Why? then disable csf on one of receiver's device (or both) using systemctl stop csf lfd and now you'll see receiver quickly appear on window
Another example: Syncthing continuous synchronization
It works perfectly while has csf but with different networks over internet. again, it doesn't work good on lan while csf enabled