Startup reporting of: presumed-IP, public-IP, public-TCP-openness of bound TCP ports

[cameronelliott]

terms:
presumed-ip: the IP address sfu1 has decided to register using DDNS, if it is doing so.
public-ip: the public IP address of sfu1 if the presumed-ip is not public, for natted situations.

It would be super nice to provide a service which enables sfu1 to tell the user at startup
the following:

1. is presumed-ip a public ip or not.
2. your public-ip is XXXX
3. port 80 and/or 443 is, is-not open at your public-ip

this would go a long way to making sfu1 even easier.