Forefront UAG DirectAccess Troubleshooting: DNS64 Startup, Shutdown, and General Events

The DNS64 complements a NAT64 deployment by translating IPv4 DNS responses to IPv6 DNS responses using a NAT64 prefix defined in the Forefront UAG DirectAccess Configuration Wizard. Some of the following DNS64 startup, shutdown and general related Event IDs may appear in the Windows Event Viewer when a Forefront UAG Activation fails, or when the Microsoft Forefront UAG DNS64 Service is started. Resolutions are provided for the Error and Warning messages where possible.

Event ID	Message
20001	No NAT64 prefix is configured. UAG DNS64 service cannot start.
20002	The NAT64 prefix configured is not valid. Configure a valid IPv6 address without the prefix notation. The UAG DNS64 service cannot start.
20003	The configured monitoring base interval time in seconds is not valid. Configure an integer greater than or equal to [%1]. The UAG DNS64 service cannot start.
20004	Cannot read the configuration files.
20005	One of the configuration values ([%1]) is not valid. This can be safely ignored but may cause unexpected behavior.
20006	The performance counter category [%1] does not exist. These performance counters will not be available in Performance Monitor.
20007	Error connecting to performance counter: [%1]:[%2]. The performance counter does not exist. Error: %3.
20008	A UAG DNS64 internal error occured.
20009	A UAG DNS64 internal error occured. More info: %1

20001 - No NAT64 prefix is configured. UAG DNS64 service cannot start.

Cause—Essential configuration settings are missing from the DNSALGConfiguration.xml file.

Solution—Check permissions:

Verify that the <Forefront UAG installation directory>\common\bin\da\dnsalg\DNSALGConfiguration.xml file exists, and that the folder has write permissions assigned to the local system account.
Reapply the Forefront UAG DirectAccess configuration, and then reactivate Forefront UAG.

20002 - The NAT64 prefix configured is not valid. Configure a valid IPv6 address without the prefix notation. The UAG DNS64 service cannot start.

Cause—The IPv6 prefix in the DNSALGConfiguration.xml file is not valid.

Solution—Check permissions and the NATPrefix entry:

Verify that the <Forefront UAG installation directory>\common\bin\da\dnsalg\DNSALGConfiguration.xml file exists, and that the folder has write permissions assigned to the local system account.
Ensure that the NATPrefix entry contains a valid IPv6 address, and does not include the prefix notation.
Reapply the Forefront UAG DirectAccess configuration, and then reactivate Forefront UAG.

20003 - The configured monitoring base interval time in seconds is not valid. Configure an integer greater than or equal to [%1]. The UAG DNS64 service cannot start.

Cause—The monitoring base interval is not valid.

Solution—Reconfigure the monitor base interval:

Open <Forefront UAG installation directory>\common\bin\da\dnsalg\DNS_Service.exe.config with a text editor.
Set MonitoringBaseIntervalSeconds to an integer value specified in the range specified in the Event message.
Restart the Microsoft Forefront UAG DNS64 Service (DnsAlgSrv) service.

20004 - Cannot read the configuration files.

Cause— The DNSALGConfiguration.xml configuration file does not exist.

Solution—Check permissions:

Verify that the <Forefront UAG installation directory>\common\bin\da\dnsalg\DNSALGConfiguration.xml file exists, and that the folder has write permissions assigned to the local system account.
Reapply the Forefront UAG DirectAccess configuration, and then reactivate Forefront UAG.

20005 - One of the configuration values ([%1]) is not valid. This can be safely ignored but may cause unexpected behavior.

Cause—When an IPv6 address in the DNSALGConfiguration.xml configuration file is invalid. The IP address should be the second 6to4 address configured on the external-facing adapter and is used by the socket listener.

Solution—Ensure that the IP address in <Forefront UAG installation directory>\common\bin\da\dnsalg\DNSALGConfiguration.xml> is valid, reapply the Forefront UAG DirectAccess configuration, and then reactivate Forefront UAG.

20006 - The performance counter category [%1] does not exist. These performance counters will not be available in Performance Monitor.

Cause—The performance counter categories are created when Forefront UAG is installed. When a performance counter category has been deleted Event 20006 occurs.

Solution—To re-create performance counters you must reinstall Forefront UAG.This message can be ignored but the specified performance counter category will be unavailable.

20007 - Error connecting to performance counter: [%1]:[%2]. The performance counter does not exist. Error: %3.

Cause—The performance counters are created when Forefront UAG is installed. When performance counters have been deleted Event 20007 occurs.

Solution—To re-create performance counters you must reinstall Forefront UAG. This message can be ignored but the specified performance counters will be unavailable.