Normally SOAPAction is used to route request messages to the appropriate methods. This has many problems, not the least of which is its reliance on HTTP. For the reasons explained in Chapter 6, avoid using SOAPAction if you can. By default, ASP.NET Web services rely on SOAPAction. You can change that by adding a SoapDocumentServiceAttribute attribute to the Web service class and setting its RoutingStyle property to SoapServiceRoutingStyle.RequestElement. See Chapter 6 for more details on the RoutingStyle property.