Find the client's provider from the applet

[zebulon]

I have an applet from which I would like to know what is the provider of the
client machine.
(it is online there http://www.testadsl.net/portail/newtests/)

I guess it should be possible..

I was thinking about 2 options :
-From the applet I can open a socket to the server but I can trace route to
the server ? In that case I would figure out the gateway of the provider ..

- I suppose each provider as its own range of ip (submask).. but where can I
find that info (looked on ripe.net but didn't find that ) (And I am
intersted by French providers)

Thanks by advance