I'm building a web application using WCF that will be consumed by other applications as a service. Our app will be installed on a farm of web services and load balanced for scalability purposes. Occasionally we run into problems specific to one web server and we'd like to be able to determine from the response which web server the request was processed by and possibly timing information as well. For example, this request was processed by WebServer01 and the request took 200ms to finish.

The first solution that came to mind was to build an ISAPI filter to add an HTTP header that stores this information in the response. This strikes me as the kind of thing somebody must have done before. Is there a better way to do this or an off-the-shelf ISAPI filter that I can use for this?

Thanks in advance