Name resolution and proper DNS server configuration is vital to the functionality of DirectAccess. When performing initial configuration of DirectAccess, or making changes to the DNS server configuration after initial configuration, you may notice the operations status for DNS indicates Critical, and that the operations state shows Server responsiveness.
Highlighting the DNS server on the Operations Status page and viewing the details shows that DNS is not working properly with the following error message:
None of the enterprise DNS servers <IPv6_address> used by DirectAccess clients for name resolution are responding. This might affect DirectAccess client connectivity to corporate resources.
There are a number of things that can contribute to this problem, but a common cause is an error made when assigning a DNS server to a specific DNS suffix. An inexperienced DirectAccess administrator might specify the IPv4 address of an internal corporate DNS server, which is incorrect. The DNS server IPv4 address should be the address assigned to the DirectAccess server’s internal network interface.
The best way to ensure that the DNS server is configured correctly for DirectAccess is to delete the existing entry and then click Detect.
An IPv6 address will be added automatically. This is the IPv6 address of the DNS64 service running on the DirectAccess server, which is how the DNS server should be configured for proper DirectAccess operation.
Once the changes have been saved and applied, the DNS server should once again respond and the status should return to Working.