Real World XML Web Services: For VB and VB .NET Developers

5.7. The ISAPI Listener

All examples in this chapter have used an ASP listener to receive and process SOAP requests. The toolkit's documentation recommends that for maximum performance you use an ISAPI listener. I haven't run benchmarks comparing the performance of ISAPI versus ASP listeners but intuitively, I agree with the documentation's recommendation. You should use an ASP listener only if you want to preprocess incoming SOAP messages before passing them on to SoapServer30; otherwise you should use an ISAPI listener.

The ISAPI listener is based on the ISAPI extension architecture where a file type (a file extension) is mapped to a DLL that knows how to handle requests for files of that type.

The toolkit's ISAPI listener is an ISAPI extension ...