Log4Net & WCF IErrorHandler - ServiceSecurityContext.Current.WindowsIdentity.Name returns NullReferenceException

I am using a WCF Service and I have implemented IErrorHandler. In the HandleError method, I want to retrieve the caller's username in order to set a ThreadContext property for Log4Net (to save the username along with the exception details in SQL Server)

My code is working well if I avoid trying to retrieve the caller's username.

This is the line of code inside the HandleError method which is returning a NullReferenceException:

string username = ServiceSecurityContext.Current.WindowsIdentity.Name;

It seems that at the point the HandleError method of IErrorHandler kicks in, the original caller information has been disposed.

Does anyone have any idea how I can retrieve the caller's username inside the HandlerError method of IErrorHandler?

Thanks for your help!

Solution

Thanks to those who responded to help. My security appears to be configured correctly but I cannot retrieve the username in the HandleError method of the IErrorHandler interface in the WCF service. However, I am able to retrieve the username in the ProvideFault method. So, I declared a class level variable in the ErrorHandler (IErrorHandler) class which is set during the ProvideFault method and then read and logged with the exception in the ErrorHandler method. This is a "workaround" and not my preference, but unfortunately I cannot seem to access the security context inside the HandleError method.

Here is a sample of the code:

public class ErrorHandler : IErrorHandler, IServiceBehavior
{
    private string username = null;

    public bool HandleError(Exception error)
    {
        //Log the exception along with the username.
        //...logging call including the username class member string...

        //Return true to indicate we have performed our behaviour.
        return true;
    }

    public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
    {
            //Retrieve the username.
            username = ServiceSecurityContext.Current.WindowsIdentity.Name;
    }
}