(Answer) (Category) VNC FAQ-o-Matic : (Category) VNC and Firewalls :
What's the *Easiest* solution to VNC and firewalls/routers?
Forgive the slight self-promotion here. :)

If you use (Xref) EchoVNC on both your VNC Viewer side 
and VNC Server side, you can connect one to the other
across the Internet without any firewall or router
adjustments whatsoever.

No, really. Have a look here:

http://www.echovnc.com
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