Windows Server VPS as L2TP VPN Server with one NIC

Question

I just installed the OpenVPN Access Server on a Linux VPS (Azure Virtual Maschine) and it works perfectly! (The purpose is to be online at "unsafe" locations.)

But I would prefer the a Windows Server with a running L2TP VPN Server. But I wasn't able to simple share the internet through VPN, because the Wizard demands two Network Interfaces.

Has anyone accomplished to run a VPN Server on Windows Server with Internet Sharing with one Network Interface?

Answer 1

Basically, you can't use a single card server to share your internet connection, it requires two. One for the internal network and one for external however, a workaround is to install a "Microsoft Loopback Adapter". Using Microsoft Loopback Adapter, you can use Internet Connection Sharing to provide Network Address Translation (NAT) and share a single connection to the Internet between the host operating system and one or more virtual machines.

To install the Loopback Adapter, go to Device Manager, right click first node which is your computer and choose "Add legacy hardware". Alternatively, open control panel and type "add hardware" in the search box, and you'll see a result under Device Manager for "Install drivers for older devices with Add Hardware Wizard". Next, choose "Install the hardware that I manually select from a list (Advanced)", then choose "Network Adapters" (next), then choose "Microsoft" as the manufacturer, then "Microsoft Loopback Adapter" from the Network Adapter list.

Once installed, you must configure it. Go to it's IPV4 properties and give it an IP address in the range of local addresses for your RRAS VPN Server. Also, give the loopback adapter a subnet mask that matches your VPN's address range (e.g. 255.255.255.0). Leave the default gateway and DNS servers blank.

In order to share internet on your VPN connection, don't forget to manually enable NAT with RRAS as well.

Answer 2

You do it nicely with single Interface in Azure. Here is fully automated solution to deploy L2TP VPN server in Azure. https://artisticcheese.wordpress.com/2021/03/01/l2tp-vpn-via-arm-template-in-azure/