Sometimes I need to share a big file between computers in the same network. Most alternatives are too slow in my opinion and sometimes is not worth to install a specific program.
This is why I usally just use Python. It’s installed in all Linux systems and it can be easily installed if not. Usually you can just run python -m http.server on the desired directory and connect to the server using any browser in the other computer to download.
I also wrote a Python script in order to send the file using socket and it’s pretty efficient.