UPnP protocol, this would help many new node operators. There is steps required for the node operator to enable thier router for UPnP. These steps are much easier than getting the correct port forwarding.
On install of the application should ask to add a firewall rule(s) to be added for port forwarding to the correct port. At lease this can be done on windows.
Believe this would make a big impact on getting the lowest common denominator to start as an node operator with little networking knowledge.