I'm getting a timeout error when I try to connect to my remote Linux server with VNC Viewer (5.1.0) . I found a support thread from 2011 titled "Norton 360 Firewall and Real VNC". Thought I'd found the solution but after trying "Rootkit Eradicator" recommendations, I still can't connect. Specifically what I did was:
"pull up Norton's main screen, select "Settings" from the menu at top, and then pick "My Network" from the left-hand column of the screen that brings up. From there, click "Configure" for "Trust Control," and make sure all the computers you want to be able to connect are set to at least "Shared."."
On the server running 360 you need to go into smart firewall settings and click program rules. Then find the VNC server and change it from Auto to Allow.
The "allow" setting lets it recieve communications that do not originate from the server (incoming connections).
You also need to forward the correct ports to that system of using a router.
Giving trust to a system in the network security map only works for systems on the LAN, it can't be used for systems out in the internet.