Always On VPN Protocol Recommendations for Windows Server Routing and Remote Access Service (RRAS)

Always On VPN Protocol Recommendations for Windows Server Routing and Remote Access Service (RRAS)Windows 10 Always On VPN is infrastructure independent and can be implemented using third-party VPN devices. It is not necessary to deploy any Windows servers at all to support an Always On VPN solution. However, in a recent blog post I outlined some compelling reasons to consider using Windows Server 2016’s Routing and Remote Access Service (RRAS) feature to terminate VPN connections. RRAS supports both modern and legacy VPN protocols, each with their own advantages and disadvantages. The choice of which protocols to support will be determined by many factors, but it is important to understand the capabilities of each to make an informed decision.

RRAS VPN Protocols

Windows RRAS supports the following VPN protocols.

  • Internet Key Exchange version 2 (IKEv2) – RFC7296
  • Secure Sockets Tunneling Protocol (SSTP) – Microsoft
  • Layer Two Tunneling Protocol over IPsec (L2TP/IPsec) – RFC2661
  • Point-to-Point Tunneling Protocol (PPTP) – RFC2637

There are pros and cons associated with each of these VPN protocols. Here’s a breakdown of each.

IKEv2

This IPsec-based VPN protocol is the preferred choice for most deployments. IKEv2 provides the best security and performance, with native features that enhance mobility. This latest version of IKE (v2) features streamlined messaging during connection establishment and enhanced session management that reduce protocol overhead and improve performance.

Advantages: Best security and performance.
Disadvantages: Firewalls may block required UDP ports.

SSTP

SSTP is an excellent alternative to IKEv2. It uses industry standard Transport Layer Security (TLS), making it widely accessible from most locations. It provides good security out of the box, but can be improved upon with additional configuration. SSTP lends itself well to load balancing, making it much easier to scale out than IKEv2. Optionally, TLS can be offloaded to an Application Delivery Controller (ADC) to reduce resource utilization on the RRAS server and further improve performance.

Advantages: Easy to configure with firewall friendly access.
Disadvantages: Not as secure IKEv2.

L2TP

While technically supported for Always On VPN, L2TP is a legacy VPN protocol that offers no real advantages over IKEv2. Its use is unnecessary and should be avoided.

Advantages: None.
Disadvantages: Firewalls may block required UDP ports.

PPTP

PPTP is considered an obsolete VPN protocol with many known security vulnerabilities. Its use should be avoided at all costs.

Advantages: None.
Disadvantages: Insecure.

Summary

Implementation best practices dictate that IKEv2 and SSTP be enabled to support Windows 10 Always On VPN connections when using Windows Server 2016 RRAS. The use of L2TP/IPsec and PPTP should be avoided. The combination of IKEv2 and SSTP will provide the best security and availability for remote workers. Clients that can establish IKEv2 VPN connections can take advantages of the security and performance benefits it provides. SSTP can be enabled as a fallback for clients that are unable to establish an IKEv2 connection due to restricted firewall access.

Always On VPN Hands-On Training

Interested in learning more about Windows 10 Always On VPN? Hands-on training classes are now forming. More details here.

Additional Resources

Frequently Asked Questions about Microsoft’s PPTP Implementation

Always On VPN and Windows Server Routing and Remote Access Services (RRAS)

Windows 10 Always On VPN and the Future of DirectAccess 

5 Things DirectAccess Administrators Should Know about Always On VPN 

3 Important Advantages of Windows 10 Always On VPN over DirectAccess 

Windows 10 Always On VPN Hands-On Training Classes

Always On VPN and Windows Routing and Remote Access Service (RRAS)

Windows 10 Always On VPN hands-on training classes now forming. Details here.

Always On VPN and Windows Routing and Remote Access Service (RRAS)

As I’ve written about in the past, Windows 10 Always On VPN has many advantages over DirectAccess. One of the most important features is that Always On VPN is completely infrastructure independent. Always On VPN is implemented entirely on the client side, so there is no reliance on Windows infrastructure servers at all. In theory, you could deploy an Always On VPN solution using an entirely third-party backend infrastructure. This is crucial because many organizations already have security infrastructure in place today. However, there are still some compelling reasons to choose Windows Server 2016 as the VPN server to support Windows 10 Always On VPN.

Considerations for Windows Server

Windows Server 2016 includes a very capable VPN server in the Routing and Remote Access Service (RRAS) role. Using Windows Server 2016 RRAS will meet the requirements for many deployment scenarios. RRAS also provides some unique advantages too. The following are some important considerations for choosing RRAS for VPN.

Easy to Deploy

The RRAS role in included in all Windows server network operating systems and can be enabled easily using the GUI or PowerShell. RRAS is mature and well-documented, making installation and configuration simpler. In fact, all of the Microsoft Windows 10 Always On VPN documentation guidance references RRAS.

Reduced Costs

No investment in proprietary hardware is required, because RRAS runs on Windows Server 2016 and can be deployed on existing virtual infrastructure. Deploying additional RRAS virtual machines enables quick and efficient scaling up of the solution without the need to deploy additional expensive hardware. Importantly, RRAS requires no additional per-client or per-device licensing. In addition, RRAS can be managed using existing Windows administration skill sets and does not require dedicated, and often expensive solution-specific expertise.

Modern Protocol Support

RRAS includes support for modern VPN protocols such as Internet Key Exchange version 2 (IKEv2) and Secure Socket Tunneling Protocol (SSTP). IKEv2 is the protocol of choice or most deployments, and is required for supporting the device tunnel. SSTP is a firewall-friendly protocol that ensures remote Windows clients can connect from anywhere. Layer Two Tunneling Protocol over IPsec (L2TP/IPsec) and Point-to-Point Tunneling Protocol (PPTP) are also supported for legacy client compatibility.

Summary

Although Windows 10 Always On VPN can be implemented using third-party VPN servers, it’s important not to overlook Windows server either. Windows Server 2016 RRAS has some important advantages over third-party infrastructure. RRAS is mature and well understood, with an abundance of published documentation available. Leveraging RRAS eliminates the need for costly proprietary hardware and client licensing, while at the same time reducing administrative overhead and streamlining support. RRAS also includes native support for modern VPN protocols, ensuring reliable client connectivity from any location.

Additional Resources

3 Important Advantages of Windows 10 Always On VPN over DirectAccess 

Windows 10 Always On VPN and the Future of DirectAccess 

5 Things DirectAccess Administrators Should Know About Always On VPN 

 

 

3 Important Advantages of Always On VPN over DirectAccess

3 Important Advantages of Always On VPN over DirectAccess Windows 10 Always On VPN hands-on training classes now forming. Details here.

Windows 10 Always On VPN provides seamless and transparent, always on remote network access similar to DirectAccess. The mechanics of how it is delivered and managed are fundamentally different, as I discussed here. Some of these changes will no doubt present challenges to our way of thinking, especially in the terms of client provisioning. However, Always On VPN brings along with it some important and significant advantages too.

No More NLS

A Network Location Server (NLS) is used for inside/outside detection by DirectAccess clients. By design, the NLS is reachable by DirectAccess machines only when they are on the internal network. NLS availability is crucial. If the NLS is offline or unreachable for any reason at all, DirectAccess clients on the internal network will mistakenly believe they are outside the network. In this scenario, the client will attempt to establish a DirectAccess connection even though it is inside. This often fails, leaving the DirectAccess client in a state where it cannot connect to any internal resources by name until the NLS is brought back online.

Always On VPN eliminates the frailty of NLS by using the DNS connection suffix for trusted network detection. When a network connection is established, an Always On VPN connection will not be established if the DNS connection suffix matches what the administrator has defined as the internal trusted network.

Full Support for IPv4

DirectAccess uses IPv6 exclusively for communication between remote DirectAccess clients and the DirectAccess server. IPv6 translation technologies allow for communication to internal IPv4 hosts. While this works for the vast majority of scenarios, there are still many challenges with applications that do not support IPv6.

Always On VPN supports both IPv4 and IPv6, so application incompatibility issues will be a thing of the past! With full support for IPv4, the need for IPv6 transition and translation technologies is eliminated. This reduces protocol overhead and improves network performance.

Infrastructure Independent

3 Important Advantages of Always On VPN over DirectAccess Windows servers are required to implement DirectAccess. Always On VPN can be implemented using Windows servers as well, but it isn’t a hard requirement. Always On VPN is implemented entirely on the Windows 10 client, which means any third-party VPN device can be used on the back end, including Cisco, Checkpoint, Juniper, Palo Alto, Fortinet, SonicWALL, F5, strongSwan, OpenVPN, and others! This provides tremendous deployment flexibility, making it possible to mix and match backend infrastructure if required. For example, a Windows RRAS VPN server with Palo Alto and SonicWALL firewalls could all be implemented at the same time (using the Windows built-in VPN client). Importantly, making changes to VPN infrastructure is much less impactful and disruptive to clients in the field. VPN devices can be upgraded, replaced, and moved internally without requiring corresponding policy changes on the client.

Additional Information

Always On VPN and the Future of Microsoft DirectAccess 

5 Things DirectAccess Administrators Should Know about Always On VPN 

Contact Me

Have questions about Windows 10 Always On VPN? Interested in learning more about this new solution? Fill out the form below and I’ll get in touch with you.

Always On VPN Device Tunnel Configuration Guidance Now Available

Always On VPN Device Tunnel Configuration Guidance Now AvailableWindows 10 Always On VPN hands-on training classes now forming. Details here.

When Always On VPN is configured for Windows 10, the VPN connection is established automatically when the user logs on to their device. This differs fundamentally from DirectAccess, where the connection is established by the machine, before the user logs on. This subtle but important difference has some important ramifications. For example, it means that a user cannot use Always On VPN until they’ve logged on to their device at least once while connected to the corporate network. DirectAccess doesn’t have this limitation, as a connection to an on-premises domain controller is available to authenticate a new user upon first logon.

Device Tunnel Support

To address this shortcoming with Always On VPN, and to provide better feature parity with DirectAccess, Microsoft introduced an update to Windows 10 in the recent Fall Creators update (v1709) that allows for the configuration of a device tunnel for Windows 10 Always On VPN. Once enabled, the device itself can automatically establish a secure remote connection before the user logs on. This enables scenarios such as device provisioning for new remote users without cached credentials. It also enables support for password reset using CTRL+ALT+DEL.

Manage Out

Device tunnel for Windows 10 Always On VPN also enables important manage out scenarios that DirectAccess administrators have come to rely upon. With a device tunnel configured, administrators can initiate connections to remote connected Always On VPN clients to provide remote management and support, without requiring a user to be logged on at the time.

Requirements

To support an Always On VPN device tunnel, the client must be running Windows 10 Enterprise or Education v1709 or later. The computer must be domain-joined and have a machine certificate installed. Device tunnel can only be configured using the built-in Windows 10 VPN client (no support for third-party clients) and the IKEv2 protocol must be used.

Caveat

When configuring a device tunnel, traffic filters can be implemented to restrict communication to only those internal resources required, such as domain controllers, Windows Server Update Services (WSUS) or System Center Configuration Manager (SCCM) servers. However, when traffic filters are used, no inbound traffic to the client is allowed. If manage out is required over the device tunnel, traffic filters cannot be configured. Microsoft expects to remove this limitation in a future update.

Provisioning and Documentation

Configuring and provisioning a Windows 10 Always On VPN device tunnel is similar to the process for the Always On VPN connection itself. A VPN profileXML file is created and then deployed via a Mobile Device Management (MDM) solution such as Microsoft Intune. Optionally, the VPN profileXML can be deployed using SCCM or PowerShell. Additional information about Windows 10 Always On VPN device tunnel configuration, including a sample profileXML and PowerShell script, can be found here.

Additional Resources

Configure a VPN Device Tunnel in Windows 10

Always On VPN and the Future of DirectAccess

5 Things DirectAccess Administrators Should Know about Always On VPN

%d bloggers like this: