I'm currently using a raspberry pi 3. Even though it comes with a built in wifi card, it does not seem to find any wlan interface. I think this is due to the operating system being an older version. To fix this problem, I tried to connect the pi to the internet through my laptop using an ethernet cable and update it. Installing a new operating on the SD-Card is out of question, since the pi is not mine and might have important data/configuration. The problem I'm facing right now is that the pi cannot connect to the internet. I tried to configure the connection method to 'shared to other computers', it did not work. I also followed this tutorial https://www.raspberrypi.org/forums/viewtopic.php?t=6997&p=87671
At first it worked, the pi would connect to it, but I recently upgraded the Kernel on my Laptop and since then it is not working anymore.
I'm starting to get really desperate, I couldn't find anything to solve this problem. Is it possible that the firewall is blocking the connection? If so how can I configure it?
NOTE: My laptop is Ubuntu 16.04