Take a look at http://metalab.unc.edu/LDP/HOWTO/mini/IP-Masquerade.html
IP masquerading is a simple form of NAT.
There are a couple different ways to implement a VPN
via pppd and ssh http://metalab.unc.edu/LDP/HOWTO/mini/VPN.html
via vpnd http://www2.crosswinds.net/nuremberg/~anstein/unix/vpnd.html
via IPSEC http://www.xs4all.nl/~freeswan/
If you connect a private network (10.0.0.0, 192.168.x.y) to the internet,
the packets will probably just be dropped by the first router. I don't know
that is it illegal. It just won't work.
I don't see any reason you can't tunnel through the internet, where the
tunnelled net is a private network. That is it's purpose.
> Hi Netter,
> Sometimes ago, I asked this newsgroup on the existence of NAT (Network
> Translation) for Linux and received information on IP tunelling, instead.
> I figured out that there exists no NAT software for Linux. I hope some of
> can tell me that I am wrong.
> Anyway, I do have a question on NAT (or IP tunelling) for Linux. Is it
> to use the IP tunelling to let your private net (192.x.x.x) surf or
> the Internet?
> Robert Young,