Quote from TopGun:
DarkWolf
When you say it all goes down a VPN tunnel what do you mean ?
Why is it invisible ? inside tunnel
Do you use a VPN client to connect to your ISP via ADSL service ?
VPN tunnels are set up between two end points - ie your PC and some other device like at your ISP - when established effectively you are directly connected to the "private" side of the VPN terminating device.
ADSL normally uses PPPoE and you connect to your ISP's DSLAM - I use Telstra and this is how they are set up
I can traceroute to anywhere and see the full path with all hops etc
Yes, you're right about the VPN. However, Internode has a VPN set up with Telstra. They route traffic down the VPN tunnel to their main base in Adelaide. Because of this, if you're routing traffic through Internode, you can't see the VPN tunnel itself (you're not running the tunnel, Internode is). The end points are your exchange, and Internode's routers down in Adelaide.
A VPN connects what may be multiple pathways to one network into one, logical hop. All other hops that the tunnel uses can't be seen to traffic operating inside the tunnel.
Ok, an example:
Let's say we run a network - 192.168.0.0/24, and our router is 192.168.0.254. Let's say we want to establish a VPN tunnel to someone else's network - say it's 192.168.1.0/24.
Right, now let's say that, without the VPN tunnel, when we do a traceroute from our router to theirs (192.168.1.254), we get these responses: 192.168.0.254->172.16.203.3->172.17.203.1->192.168.1.254. Make sense? We go through four routers (ours, theirs, and two in the middle) to contact their network. Without the VPN.
Now, we establish a VPN tunnel from 192.168.0.0/24 to 192.168.1.0/24, connecting the two routers as endpoints. Now, the VPN tunnel "hides" that route as a single link. So if we do a traceroute now, from a host inside our network, we get these responses: 192.168.0.254->192.168.1.254. Our internal clients have no idea that they've gone through a VPN tunnel, and no idea of the two routers that are in reality sitting in the middle. The VPN hides all that stuff for you.
You only need to run a VPN client on YOUR machine if your machine is functioning as the router (ie, you dial up with a modem or something). Otherwise, the router runs the VPN client, and sets up the tunnels for you. It's really very cool :P
I can tell you more if you want to know - my company's network is all based on VPN's running through Cisco routers.
Darkwolf.