Implementing a WCF service on an Active Directory domain using a ServiceHost in a Windows Service with Windows authentication and a non-system user service account

So, as it turns out, when you want to implement a WCF service on an Active Directory domain using a ServiceHost in a Windows Service with Windows authentication and a non-system user service account, you have to jump through a few hoops for the configuration. I kept getting the error message "A call to SSPI failed. see inner exception". The inner exception is "The target principal name is incorrect.". Like many other people, I kept thinking it had to do with authentication of the *client*. As it turns out, like those other people, I was wrong. It was to do with *verification of the service account running the service*. This is presumably because the *service user is a domain user service account*. To get this scenario working, you have to specify the name of the service user account as the 'userPrincipalName' in the 'identity' element of the 'endpoint' element for your service, like so:

<configuration>
<system.serviceModel>
<services>
<service name="MyProject.MyService">
<host>
<baseAddresses>
<add baseAddress="net.tcp://localhost:12345/MyService"/>
</baseAddresses>
</host>
<endpoint name="MyServiceTcpEndpoint"
 address=""
 binding="netTcpBinding"
 bindingConfiguration="MyServiceTcpBinding"
 contract="MyProject.IMyService">
<identity>
<userPrincipalName value="MyDomainName\MyServiceUserName"/>
</identity>
</endpoint>
<endpoint address="mex" binding="mexTcpBinding" contract="IMetadataExchange" />
</service>
</services>
<bindings>
<netTcpBinding>
<binding name="MyServiceTcpBinding"
transferMode="Buffered"
maxReceivedMessageSize="65535">
<security mode="Transport">
<!-- Use Windows authentication to ensure that we at least have authentication if not encryption -->
<transport clientCredentialType="Windows" />
</security>
</binding>
</netTcpBinding>
</bindings>
</system.serviceModel>
</configuration>

Now you'll get proper connections and authentication via Windows.