how to connect to host computer from android device

[robert-elles]

After successful reverse proxy start the android tablet can access the host computers internet. So far so good. But how can the android tablet connect to a port on the host. For example on the host i have a vnc server running. On the android tablet I want to connect to that vnc server on the host. I try pinging the host but I am not even sure which ip address to ping.
How can the android tablet see the host in the network?