To redirect all traffic from VPN clients through the VPN server, you have to configure NAT.

At this step I assume that you have OpenVPN configured properly, if not please refer to the manual ​http://community.openvpn.net/openvpn/wiki/Easy_Windows_Guide.

1. Enabling IP forwarding Press Windows+R and type:

regedit.exe

Now navigate to the:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Tcpip\Parameters

and set

IpEnableRouter

to 1

2. Installing role Open ServerManager and click on Install role

Click Next

Wait till Windows complete instaling new role.

3. Configuring NAT Open Routing and Remote access console from Administrative Tools, right click on your server local name and select

Configure and Enable Routing and remote Access

In a wizard click on Network address translation(NAT)

In next step select your network card that have access to internet and click Next.

Last thing to do is to select VPN Tap-win32 network card and finish wizard.

NAT should be working from now.