在开发WCF或者xml webservice，而客户端不是.net； 或者是用.net开发其它语言写的web service的时候。
fiddler是非常有用的工具用于抓取soap message，并进行分析。
但是当你使用fiddler监控对本地service的调用是，经常会看不到任何http包。
解决方法很简单， 使用localhost.而不是localhost.
例如http://localhost.:4543/wcfapp 而不是 http://localhost:4543/wcfapp
fiddler: http://www.fiddler2.com/fiddler2/
What is Fiddler?
Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet. Fiddler allows you to inspect traffic, set breakpoints, and "fiddle" with incoming or outgoing data. Fiddler includes a powerful event-based scripting subsystem, and can be extended using any .NET language.
Fiddler is freeware and can debug traffic from virtually any application that supports a proxy, including Internet Explorer, Google Chrome, Apple Safari, Mozilla Firefox, Opera, and thousands more. You can also debug traffic from popular devices like Windows Phone, iPod/iPad, and others.