Quote Originally Posted by metguru
Are you saying a router would be necessary?
Yes. It doesn't matter if it's a "hardware router" or just a computer configured to be a router. You can use a Windows server or Linux box if you want to. IPCop makes it pretty easy. http://www.ipcop.org/

The part that confuses me about it is that, don't all the computers in one network all have the same external IP? so how does it know which computer to connect to if i just have a switch?
The router will handle that. If you have a DSL modem, it is most likely a router. Otherwise you couldn't have multiple PCs connected to the internet. Keep in mind that the capabilities of the "modem" that they gave you are very limited when it comes to routing. I'd configure it to "static NAT" to a real router which has the VPN capabilities.