The simplest case if you set up a VPN connection using the Network Manager inside one of your VMs. Setting up such a connection is really not Qubes specific and it is documented in Your Operating system documentation.
If you using the Qubes default OS (Fedora): [Establishing a VPN Connection](http://docs.fedoraproject.org/en-US/Fedora/18/html/System_Administrators_Guide/sec-Establishing_a_VPN_Connection.html)
The Qubes specific part is choose the right VM for the VPN client:
### NetVM
The simplest case if you set up a VPN connection using the Network Manager inside your NetVM. Because the [NetworkManager?](/wiki/NetworkManager) already started you are ready to set up your VPN connection. However this has some disadvantages:
- You have to place (and probably save) Your VPN credentials inside the NetVM wich is directly connected to the outside world
- All your AppVMs wich are connected to the NetVM will be connected to the VPN (by default)
### ProxyVM
One of the best thing in Qubes that you can use a specian type of VMs called ProxyVM (or FirewallVM). The special thing is that your AppVMs see this as a NetVM, and the NetVMs see it as an AppVM. Because of that You can place a ProxyVM between your AppVMs and Your NetVM. This is how the default firewall VM is working.
Using a ProxyVM to set up a VPN clinet will gives you the ability to:
- Separate your VPN credentials from Your AppVM data.
- You can easily controll wich of your AppVMs are connected to your VPN by simply set it as a NetVM of the desired AppVM.
- create a new VM and check the ProxyVM radiobutton
- add the network-manager service to this new VM
- strart the new ProxyVM and set up Your VPN as described in the Network Manager documentation linked above.
- connect your AppVMs to use the VPN service.
### AppVM
While the Network Manager is not started here (for a good reason) You can configure any kind of VPN client in your AppVM as well, however it is only suggested if you have to use a special VPN clinet.
