I have a RaspberryPi in my private local network (example: 192.168.1.2) and I have a dedicated server (example: 99.99.99.99) from some provider. From my RaspberryPi I can connect to the server via ssh without trouble, the opposite situation is not possible. The RaspberryPi is not reachable from the internet. Now I want to reach the webserver on my RaspberryPi from the internet with some ssh brigde/tunnel. So if I enter the IP 99.99.99.99 in my browser, I want to see the website from the RaspberryPi. How it is possible?
The -R option to ssh will permit a remote tunnel to be opened towards the ssh client. So, if from the pi you run
ssh -R0.0.0.0:8080:address_of_pi:80 99.99.99.99
Then you will open an ssh and while that ssh is active anyone can go to 99.99.99:8080 and get to your pi.
You need to use 8080 as the port on the webserver address because the ssh process cannot bind to port 80 without being root.