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, 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.

Outlook Offline over DirectAccess on Windows 10

Outlook Offline over DirectAccess on Windows 10You may encounter a scenario in which Outlook on Windows 10 reports that it is working offline while connected remotely via DirectAccess. The Network Connectivity Status Indicator (NCSI) shows DirectAccess is in a connected state and all other internal resources are accessible.

Outlook Offline over DirectAccess on Windows 10

This is caused by the default settings of the IP-HTTPS tunnel interface on the DirectAccess server not advertising a default route for connected DirectAccess clients. To resolve this issue, enable default route advertising for IP-HTTPS on each DirectAccess server in the enterprise by running the following PowerShell command.

Get-NetIPInterface | Where-Object {$_.InterfaceAlias -eq “IPHTTPSInterface”} | Set-NetIPInterface -AdvertiseDefaultRoute Enabled -PassThru

Outlook Offline over DirectAccess on Windows 10

In the past I’ve heard reports of this setting being overwritten after group policy refresh. Recent testing on Windows Server 2016 does not show this behavior, however. Please report any results you may have in the comments below. Thanks!

DirectAccess Force Tunneling and Proxy Server Configuration

By default, DirectAccess is configured to use split tunneling. In this scenario, a remote DirectAccess client is connected to the internal corporate network and the public Internet at the same time. Some security administrators perceive split tunneling as a security risk, and the use of split tunneling may be prohibited by corporate security policy. In addition, enforcing web browsing policies on remote DirectAccess clients might be desired to reduce the risk of exposure from browsing unapproved web sites. In either case, force tunneling can be configured to meet these requirements.

When force tunneling is enabled, DirectAccess administrators can also define an on-premises proxy server for DirectAccess clients to use. The following is guidance for enabling force tunneling and configuring DirectAccess clients to use a proxy server to access the Internet.

Enabling Force Tunneling

To enable force tunneling, open the Remote Access Management console and perform the following steps.

  1. Expand Configuration and select DirectAccess and VPN.
  2. Click Edit on Step 1 Remote Clients.
  3. Click Select Groups in the navigation tree.
  4. Select the option to Use force tunneling.

DirectAccess Force Tunneling and Proxy Server ConfigurationFigure 1. Enable DirectAccess force tunneling in the Remote Access Management console.

Alternatively, force tunneling can quickly be enabled by opening an elevated PowerShell command window and running the following command.

Set-DAClient -ForceTunnel Enabled -PassThru

DirectAccess Force Tunneling and Proxy Server ConfigurationFigure 2. Enable DirectAccess force tunneling using PowerShell.

Configure a Proxy Server

Once force tunneling has been enabled, run the following PowerShell script to configure an on-premises proxy server for DirectAccess clients to use. Be sure to substitute the fully-qualified domain name (FQDN) and port for your proxy server in the $proxy variable below.

$gpo = (Get-RemoteAccess).ClientGpoName
$gpo = $gpo.Split(‘\’)[1]

$proxy = “proxy.corp.example.net:8080”

$rule = (Get-DnsClientNrptRule -GpoName $gpo | Where-Object Namespace -eq “.” | Select-Object -ExpandProperty “Name”)

Set-DnsClientNrptRule -DAEnable $true -DAProxyServerName $proxy -DAProxyType “UseProxyName” -Name $rule -GpoName $gpo

If multisite is enabled and Windows 7 clients are supported, run the following PowerShell script on one DirectAccess server in each entry point.

$downlevelgpo = (Get-RemoteAccess).DownlevelGpoName
$downlevelgpo = $downlevelgpo.Split(‘\’)[1]

$proxy = “proxy.corp.example.net:8080”

$downlevelrule = (Get-DnsClientNrptRule -GpoName $downlevelgpo | Where-Object Namespace -eq “.” | Select-Object -ExpandProperty “Name”)

Set-DnsClientNrptRule -DAEnable $true -DAProxyServerName $proxy -DAProxyType “UseProxyName” -Name $downlevelrule -GpoName $downlevelgpo

Remove Proxy Server

Run the following PowerShell script to remove the proxy server, if necessary.

$gpo = (Get-RemoteAccess).ClientGpoName
$gpo = $gpo.Split(‘\’)[1]

Set-DnsClientNrptRule -DAEnable $true -DAProxyType “UseDefault” -Name $rule -GpoName $gpo

$downlevelgpo = (Get-RemoteAccess).DownlevelGpoName
$downlevelgpo = $downlevelgpo.Split(‘\’)[1]

Set-DnsClientNrptRule -DAEnable $true -DAProxyType “UseDefault” -Name $downlevelrule -GpoName $downlevelgpo

Disable Force Tunneling

To disable force tunneling completely, run the following PowerShell command.

Set-DAClient -ForceTunnel Disabled -PassThru

Force Tunneling Caveats

When force tunneling is enabled, the user experience is typically poor when accessing the Internet. Web browsing performance is significantly reduced because of the added protocol overhead imposed by DirectAccess IPv6 transition technologies and IPsec encryption. This problem is further compounded when users access resources that are already encrypted, such as secure web sites. Increased packet fragmentation, along with the additional network latency caused by suboptimal network paths and increased network load on the server and Internet connection all contribute to degraded network performance for DirectAccess clients.

Force Tunneling Alternatives

Instead of enabling force tunneling, consider alternative solutions to address the security concerns associated with split tunneling. For example, implement technologies that enforce web browsing policies on the client. Many secure web gateways and next-generation firewalls (NGFW) have remote filtering capabilities that allow administrators to enforce web browsing policies on remote client machines. In addition, there are some excellent cloud-based solutions such as Zscaler and OpenDNS that can protect DirectAccess clients without the drawbacks associated with force tunneling.

Additional Information

Planning and Implementing DirectAccess with Windows Server 2016 video training course on Pluralsight
Managing and Supporting DirectAccess with Windows Server 2016 video training course on Pluralsight
Implementing DirectAccess with Windows Server 2016 Book

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