I have a home server with Ubuntu and I want to measure download and upload speed in my LAN. Is there any program for Ubuntu that will help me do this?
Well, you said download/upload speed and LAN, so I'm not sure which you actually want.
To test download/upload speed of your Internet connection:
Yes. It's is possible. With the project: https://github.com/sindresorhus/fast-cli
If you have node installed, just run
npm install --global fast-cli
Then you can use
fast to start the test.
If you don't have node installed, you can install it with
apt install nodejs
To test your LAN speed, you'll need a second computer and install
iperf on both.
Run one side as a server, the other side as the client.
On ubuntu, you can install iperf with
apt install iperf, on MacOS
brew install iperf for other operating systems you'll have to google.