The Name Resolution Policy Table (NRPT) in Windows provides policy-based name resolution request routing for DNS queries. DirectAccess uses the NRPT to ensure that only requests for resources in the internal namespace, as defined by the DirectAccess administrator, are sent over the DirectAccess connection. DNS queries for all other namespaces are sent to the DNS servers defined on the client’s network interface.
Note: This behavior changes when force tunneling is enabled. In this case, all DNS queries are sent over the DirectAccess connection with the exception of the NLS and the DirectAccess server’s public hostname(s). If force tunneling is enabled, the configuration guidance described below is not required.
Split DNS
NRPT configuration is straightforward when the internal and external namespaces are unique. However, when split DNS is used, meaning when the internal and external namespaces are the same, DirectAccess configuration is more challenging. Typically, there may be many resources that should not go over the DirectAccess connection, such as public-facing web servers, email and unified communications servers, federation servers, etc. Without additional configuration, requests for all of these services would go over the DirectAccess connection. That may or may not be desirable, depending on the requirements of the implementation.
DirectAccess Server
One crucial public resource is the DirectAccess server itself. When using split DNS, the DirectAccess implementation’s public hostname will, by default, be included in the internal namespace. In this scenario, the DirectAccess client will fail to establish a connection to the DirectAccess server.
Troubleshooting
When troubleshooting failed connectivity, the output of ipconfig will show the IP-HTTPS tunnel interface media state as “Media disconnected”.
The output of Get-NetIPHttpsState will also return an error code 0x2AF9 with an interface status “Failed to connect to the IPHTTPS server; waiting to reconnect”.
To further troubleshoot this issue, examine the output of Get-NetIPHttpsConfiguration. Test name resolution of the FQDN listed in the ServerURL field. If the issue is related to NRPT configuration, the client will fail to resolve this name to an IP address. Testing from a non-DirectAccess client should resolve correctly, however.
NRPT Configuration
If split DNS is employed, it is necessary to include the DirectAccess server’s public hostname in the NRPT as an exemption. This will cause the DNS query for the public hostname to use public DNS servers, allowing the DirectAccess client to establish a connection successfully.
To resolve this issue, open the Remote Access Management console on the DirectAccess server, highlight DirectAccess and VPN under Configuration, and then click Edit on Step 3. Select DNS, and then double-click on an empty row in the table.
Enter the public hostname for the DirectAccess deployment in the DNS suffix field (the public hostname can be found by clicking Edit on Step 2). Do NOT specify a DNS server. Click Apply, click Next twice, and then click Finish.
Note: For multisite deployments, be sure to include the public hostname for each entry point in the enterprise. Also, if multisite is configured to use GSLB, include the GSLB hostname as well.
PowerShell
Alternatively, you can run the following PowerShell commands to automatically configure the NRPT for split DNS. For multisite deployments, be sure to run these commands on at least one DirectAccess server in each site.
$hostname = Get-RemoteAccess | Select-Object -ExpandProperty ConnectToAddress
Add-DAClientDnsConfiguration -DnsSuffix $hostname -PassThru
If multisite is configured to use GSLB, run the following PowerShell commands on one DirectAccess server in the enterprise.
$gslbfqdn = Get-DAMultiSite | Select-Object -ExpandProperty GslbFqdn
Add-DAClientDnsConfiguration -DnsSuffix $gslbfqdn -PassThru
Additional Information
Troubleshooting DirectAccess IP-HTTPS Error 0x2af9
DirectAccess DNS Not Working Properly
DirectAccess DNS Records Explained
Troubleshooting Name Resolution Issue on DirectAccess Clients
Native PowerShell commands in Windows 10 make DirectAccess troubleshooting much easier than older operating systems like Windows 7. For example, with one PowerShell command an administrator can quickly determine if a DirectAccess client has received the DirectAccess client settings policy. In addition, PowerShell can be used to view the status of the connection and retrieve additional information or error codes that can be helpful for determining the cause of a failed connection. Further, PowerShell can also be used to review configuration details and perform other troubleshooting and connectivity validation tasks.
DirectAccess is a thing of beauty when everything is working as it should. When it isn’t, troubleshooting can be quite challenging. DirectAccess relies on many Windows platform technologies such as Active Directory for authentication, PKI for certificate management, group policy for settings deployment, IPsec for encryption, and IPv6 for transport. With so many dependencies, locating the source of the problem can be a difficult and daunting task.
This web site is primarily dedicated to installing, configuring, managing, and troubleshooting DirectAccess on Windows Server 2012 R2 and Windows Server 2016. However, there’s little documentation on how to properly uninstall and remove DirectAccess. This post provides guidance for gracefully uninstalling and removing DirectAccess after it has been deployed.
