Comment by blackcatsec

I mean, internet standards kept up. IPv6 is a thing, and some form of dynamic IPv6 stateful firewall hole punching a la UPnP would be useful here. Particularly if the application used the temporary address for the hole punch--because once the address lifetime ends, it's basically not going to get used again (64-bit address space). So that effectively nullifies any longer term concerns about security vulnerabilities.