I upgraded my Vine Viewer to version 3.0 and since I did, reverse VNC connection attempts fail. With the previous version, 1.2, it was working perfectly well.
When I run the VNC SC executable on the client pc, to connect to my viewer and in that way get trough firewalls and NAT routers, I can see the connection attempt in the Connection List, first as:
Status: green/orange
Name: Client IP
Host: Client IP
Port: 5500
Color: Default
Activity: Trying to connect - Client IP: 5500
and a little while later as:
Status: red
Name: Client IP
Host: Client IP
Port: 5500
Color: Default
Activity: Connection failed:Operation timed out
It seems that, since version 3.0, Vine Viewer tries to connect back to to client, after the client already tried to set up a connection or something?! That fails of course, because in that way the firewall/NAT router is a problem after all.