If you think you can play dvd on plain Debian just by inserting dvd in the tray, you are wrong. But fortunately we can install needed library easily. I did the steps described on this page.
1. Add these two line into “/etc/apt/source.list”.
deb http://download.videolan.org/pub/debian/stable/ / deb-src http://download.videolan.org/pub/debian/stable/ /
2. Add apt-key for this repository by doing this:
wget -O - http://download.videolan.org/pub/debian/videolan-apt.asc|sudo apt-key add -
3. Update the apt.
sudo apt-get update
4. Install libdvdcss2.
sudo apt-get install libdvdcss2
5. That’s it! Now you can play dvd with your favorite video player.