Uses centralised STUN servers to detect your IP address and connectivity. It is
important, especially on darknet, for Freenet to know what your IP address is
(but it may be able to pick it up from your peers, especially if you have a lot
of connections or are using opennet). STUN is used by other applications but
this is centralised so could be used to find your node. If you can use UPnP
instead then do so, but if UPnP can't find your IP address reliably you could
load this as well.
