Capture local http post traffic

Question

I have two C# winform applications on the same window machine.

• First application runs a http listener on localhost and port 4567 (not via IIS)
• Second application issue a http post (httpWebRequest) to port 4567.

I'm trying to see the post/request traffic like I normally would when viewing http traffic in Fiddler2. I have no luck so far when trying to capture this traffic with fiddler2, Charles and Wireshark.

Does anyone have insight on how to capture this traffic?

Answer 1

To see the requests to your localhost application using fiddler, please set the URL in the calling application as shown below

http://localhost.fiddler:4567/

The following post should help you out

Monitor traffic to localhost from IE or .NET

Answer 2

Fiddler cannot intercept localhost traffic, because fiddler is a proxy server, and local requests are not sent through proxy server by the .NET Framework.

To work around this, you can update your applications to send data to localhost.fiddler instead of localhost