Question : Problem: Setting up UltraVNC

I want to allow users to connect to a spare machine in the office.  I have installed UltraVNC on the server and i can connect to it remotely if i use our public IP address.  

However i do not want users connecting to the server.  How can i configure UltraVNC to connect to another machine on the network?

Answer : Problem: Setting up UltraVNC

If you setup the router to forward the default port to the spare machine. Then uou cannot connect to the server from the internet.
That's why you need to setup the router to forward the default+1 port to the spare machine. ( 5590+1 = 5591 or whatever the default port is )

If someone is conencting to the spare machine from the internet he will connect to publicIP:port
If someone is connecting to the spare machine from your local intranet he will connect to intranetIP:port

There will be no changes to the server.

www.portforward.com have a nice  port-forwarding-how-to for most routers

another thing.. make sure you set a VNC password
You don't want some thugs to connect to your machine from the internet !!!