I have a Raspberry Pi connected to my router via Ethernet, it is currently running a host for a no-ip service, both SSH and VNC are enabled. When I am connected to my home network and enter my no-ip address into putty it connects to the Raspberry Pi.
However when I connect to an open Wi-Fi network and try to connect to my Raspberry Pi using my no-ip address, putty gives a connection refused error. I know I am connecting to the correct port and my no-ip address works when I am connected to the same network as the raspberry pi. So why does the connection not work when I try to access the Pi from a different network? Once I can get the SSH connection to work properly I know I how to set up a tunnel using putty to allow me to use VNC, again I have tested this and it works.