Fiddler Web Debugger

Fiddler is a web debugging tool which is owned, developed, and distributed by Eric Lawrence.

Browse by Tags

Tagged Content List
  • Blog Post: Visual Studio 2012, IIS Express, and Fiddler

    From the mail bag... Q: When I use IE10 on Windows 8 to visit an IIS Express instance using the following URL http://ipv4.fiddler:2468/, I get an unexpected error message. HTTP/1.1 400 Bad Request Content-Type: text/html; charset=us-ascii Server: Microsoft-HTTPAPI/2.0 Date: Wed, 22 Aug 2012 19...
  • Blog Post: .NET HTTPS connections timeout on SNI TLS Warning

    Recently, a handful of folks have emailed me complaining that some HTTPS sites cannot be reached by their .NET programs or from any program when Fiddler is configured to decrypt traffic. Notably, these users only have problems when running on Windows Vista or later. So, what’s going on? When...
  • Blog Post: .NET HttpWebRequests and Expect: 100-continue

    Recently, a colleague asked me to look at a network capture in which a .NET client application’s communication with a web service was not meeting their performance goals. In particular, he noted that this was primarily a problem on high-latency networks; each of the dozens of requests took hundreds...
  • Blog Post: Fiddler and Channel Binding Tokens Revisited

    Just under a year ago, I wrote a blog post about how the new “Extended Protection” feature (also known as Channel Binding Tokens or CBT) prevented seamless decryption of certain authenticated HTTPS traffic when Fiddler is running. The quick recap is that CBT binds a set of NTLM or Kerberos...
  • Blog Post: Fiddler and IPv6-only environments

    I recently got a bug report from a user who was attempting to use Fiddler in a pure-IPv6 environment, where IPv4 is entirely disabled. On startup, he saw the following message: The problem here is an obscure one, which makes it somewhat interesting. What’s happening is that Fiddler...
  • Blog Post: Fiddler and the IE9 Release Candidate

    I’m delighted to announce that the now-available IE9 RC includes three significant enhancements for users of proxy-based debuggers like Fiddler. These improvements are: The default Connections-Per-Proxy limit has been raised from 6 to 12, improving performance and in some cases reducing...
  • Blog Post: Debugging Windows Phone 7 device traffic with Fiddler

    Back in October, I showed how to debug Windows Phone emulator traffic with Fiddler . Since then, I’ve acquired the LG Quantum phone, and naturally, one of my first goals was to start looking at the traffic from mobile Internet Explorer and some of my WP7 applications. The process for capturing...
  • Blog Post: Fiddler and Channel-Binding-Tokens

    Note: Please see this post for an update. Some users of Fiddler who have HTTPS Decryption enabled have found that some of their internal HTTPS sites that used to work properly with Fiddler now endlessly prompt for credentials while Fiddler is running. Even typing the correct credentials into the authentication...
  • Blog Post: Fiddler and the Windows Phone 7 Emulator

    Note: This post is part of a larger set on using Fiddler with Windows Phone 7 . This post covers the Windows Phone Emulator only. Recently, some developers have asked me why Fiddler no longer works with the Windows Phone 7 emulator. Fiddler properly captured traffic from the CTP version of the emulator...
  • Blog Post: Fiddler’s New Import and Export Architecture

    All versions of Fiddler support a rich extensibility model that enables developers to enhance Fiddler with new functionality useful for traffic inspection, analysis, and sharing. However, writing extensions that import traffic captured by other tools was difficult, and extensions that offered traffic...
Page 1 of 1 (10 items)