Subtitle
Or at least someone better then me with the language.

Just thought I'd put this out to you good people before I run the gauntlet of stack exchange. I'm writing plugins for our Minecraft server (so it has to be done in Java) that need to be able to tell if a player has originated from inside my network (i.e. one of my two children (real human ones, just thought I'd clarify that)) or a user from the outside world.

How do I determine the gateway/router address in Java? I have been using isSiteLocalAddres() but the issue is that this method sees anything coming through my router (192.168.1.1) as being local. Obviously it's trivial to account for this exception specifically but I'm writing something that I'd like to publish. This means that I'll need to accommodate for everyone else's router IP address.

A quick google throws up this, call me a purist but that method is horrible. My main objection being the hard coding of the Amazon website address (although I could probably come up with more reasons).

Any ideas?

A slightly less quick look suggests that the second (unaccepted) answer in the linked thread using netstat might be useful but my original question still stands.

Note to self
A bit more reading of the SO solution has this having no platform independent method possible. Way to go Java with your platform independence.

Looks like I'll need this too.