Fiddler Ideas

The free web debugging proxy for any browser, system or platform.

Make sure that filters apply to MS telemetry calls (e.g.

Microsoft telemetry calls to bypass the filters and add noise. If my filter says only show localhost, I don't expect to see calls to 

  • Guest
  • Jan 16 2018
  • Attach files
  • Eric Lawrence commented
    January 16, 2018 22:47

    Where specifically did you set the filter? If you right-click the Session and choose "Properties", what are the flags on the unexpectedly-visible Session?

    (By default, Fiddler doesn't hide sessions which resulted in HTTP Protocol Violation errors).

  • Dave Carlson commented
    January 25, 2018 20:22

    My host is slightly different:  I tried setting up a "Hide if URL contains" and "hide following hosts", but it still shows up.  I also tried adding a line in the custom rules file, but it still powers through.

    It is a protocol violation: "ProtocolViolationInRequest".

    Is there a special way I can block this specific request?

  • Dave Carlson commented
    January 25, 2018 20:22

    By block, I mean hide from the list.

  • Eric Lawrence commented
    January 29, 2018 16:41

    In the Session's Properties, you can see what exactly the protocol violation in the request is; depending on what the problem is, it reflects either a bug in the client (likely) or something that could be fixed in Fiddler.

    To cause a Session to be hidden regardless of protocol errors, you can add the word "STEALTH" to the UI-HIDE value, e.g.


    if (oSession.urlContains("")) { oSession["ui-hide"] = "STEALTH-boring boring boring...."; }
  • Rainer Koschnick commented
    February 6, 2018 09:48

    STEALTH doesn't work for me, those requests still show.

  • Eric Lawrence commented
    February 19, 2018 13:16

    Regarding the claim that "Stealth" doesn't work-- the most likely explanation is that you either wrote the rule incorrectly, or put it in the wrong place. Feel free to email me a SAZ capture demonstrating your issue. bayden at gmail dotcom.

  • James Brooks commented
    February 21, 2018 00:34

    I am also having issues with in Fiddler. My filter is on and set to "Show only the following Hosts" -- "localhost" yet I see both localhost and  I can right click on it and choose "Filter Now --> Hide v10.vort... yet after a few captures, it starts showing v10 again.  Always with 408 request body incomplete.

  • James Brooks commented
    February 21, 2018 00:41

    As a side note. Under "Filters" --> "Hide if URL contains" -->  does work in hiding it from Fiddler

  • James Brooks commented
    February 21, 2018 00:53

    Nope, spoke to soon. Adding "Hide if URL contains" did not work. Sorry.

  • Gunnar S commented
    March 8, 2018 16:08

    The problem identified by James Brooks is driving me nuts. There must be a way to stop this from showing up in Fiddler:


    HTTP/1.1 408 Request body incomplete
    Date: Thu, 08 Mar 2018 16:01:58 GMT

  • Greg Woods commented
    March 15, 2018 10:22

    My sessions list is being filled with Windows 10 telemetry calls, all with 408 errors. Even trying to remove them using fiddler script (a workaround) has failed.

    Quote: "(By default, Fiddler doesn't hide sessions which resulted in HTTP Protocol Violation errors)."


    if I have filters enabled, nothing should bypass those filters... it's just bad manners.


  • Ed Eaglehouse commented
    March 22, 2018 13:00

    I tried adding the ui-hide member on the session in the OnBeforeResponse handler using Eric's STEALTH suggestion. Fiddler threw a compilation error, "Objects of type 'Fiddler.Session' do not have such a member."

    Using automatic syntax completion and comparing other code in CustomRules.js, the urlContains function was apparently renamed uriContains. Fiddler didn't complain after I used the latter function name.

    I agree with Greg Woods' comment about filters actually filtering what you tell them to. Perhaps an additional UI option to show/hide protocol violations would be in order.

  • Ed Eaglehouse commented
    March 22, 2018 14:04

    20 minutes later, STEALTH isn't working for me, either. The telemetry responses are still showing up.

  • Greg Woods commented
    March 22, 2018 15:20

    An example of the amount of crap filling my fiddler sessions

  • Steven Lamport commented
    April 22, 2018 16:04

    I have the same issue and it drives me crazy. I have tried just about everything but these still show.