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[Solved] PR_CONNECT_RESET_ERROR, A call to SSPI failed, see inner exception.

I couldn't solve this one by myself even after googling and reading dozens of related threads on Fiddler's forum, feedback, google group, etc.

Problem: About 5% of the sites i visit doesn't work while Fiddler is active with Decrypt HTTP Traffic on.

For example, these 2 sites doesn't work for me.

https://blueproject.ro/systracer
https://learn.microsoft.com/

My OS: Windows 7 x64 SP1

Here's what I've tried so far

  • Tried Firefox, Chrome, Opera (All latest)
  • Tried uninstalling & reinstalling Fiddler
  • Tried "Reset All Certificates" and trusting again multiple times.
  • Also tried manually removing all DO_NOT_Trust certificates by using mmc.exe. I've realized that Fiddler's "Reset All Certificates" doesn't remove all Fiddler certificates in "Intermediate Certification Authorities". But it didn't fix the problem.
  • Tried all possible combination of <client>;ssl3;tls1.0;tls1.1;tls1.2

Here's the fiddler log when i open exactly this https://blueproject.ro/systracer URL in Firefox

-= Progress Telerik Fiddler Classic Event Log =- 

See http://fiddler2.com/r/?FiddlerLog for details.

23:21:05:8975 Progress Telerik Fiddler Classic Running...
23:21:11:7744 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:11:7744 Assembly 'C:\Users\User\AppData\Local\Programs\Fiddler\CertMaker.dll' was not found. Using default Certificate Generator.
23:21:11:7783 /Fiddler.CertMaker> Using .‰+˜ for certificate generation; UseWildcards=True.
23:21:12:0537 fiddler.network.https> HTTPS handshake to blueproject.ro (for #1) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:12:3154 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:12:5791 fiddler.network.https> HTTPS handshake to blueproject.ro (for #2) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:12:8467 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:13:1162 fiddler.network.https> HTTPS handshake to blueproject.ro (for #3) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:13:3994 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:13:6807 fiddler.network.https> HTTPS handshake to blueproject.ro (for #4) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:13:9541 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:14:2256 fiddler.network.https> HTTPS handshake to blueproject.ro (for #5) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:14:4912 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:14:7568 fiddler.network.https> HTTPS handshake to blueproject.ro (for #6) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:15:0225 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:15:2861 fiddler.network.https> HTTPS handshake to blueproject.ro (for #7) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:15:5576 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:15:8271 fiddler.network.https> HTTPS handshake to blueproject.ro (for #8) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:16:0947 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:16:3584 fiddler.network.https> HTTPS handshake to blueproject.ro (for #9) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326
23:21:16:6240 HTTPSLint> Warning: ClientHello record was 508 bytes long. Some servers have problems with ClientHello's greater than 255 bytes. https://github.com/ssllabs/research/wiki/Long-Handshake-Intolerance
23:21:16:8896 fiddler.network.https> HTTPS handshake to blueproject.ro (for #10) failed. System.Security.Authentication.AuthenticationException A call to SSPI failed, see inner exception. < The message received was unexpected or badly formatted

Win32 (SChannel) Native Error Code: 0x80090326

First tunnel copied from TextView

A SSLv3-compatible ClientHello handshake was found. Fiddler extracted the parameters below.

Version: 3.3 (TLS/1.2)
Random: F5 E2 DA F9 57 52 AE 1C 7B C8 D7 1E 76 A1 22 ED 18 60 8C CB 8A 0F 4F 22 CA D2 7F D0 A1 BF 0C C2
"Time": 11/2/2102 8:48:53 AM
SessionID: 4F 31 0B 04 5B AD 5B 77 F2 BA 91 AF 25 C6 E8 D5 ED 4D D9 A4 2E 3D 8C AE 78 4A C9 99 3A F9 05 C7
Extensions: 
	server_name	blueproject.ro
	extended_master_secret	empty
	renegotiation_info	00
	supported_groups	x25519 [0x1d], secp256r1 [0x17], secp384r1 [0x18], secp521r1 [0x19], ffdhe2048 [0x0100], ffdhe3072 [0x0101]
	ec_point_formats	uncompressed [0x0]
	SessionTicket	empty
	ALPN		h2, http/1.1
	status_request	OCSP - Implicit Responder
	0x0022		00 08 04 03 05 03 06 03 02 03
	key_share	00 69 00 1D 00 20 7B 47 E1 A6 18 97 36 A3 6C 5C EB 5F 37 66 21 17 E3 FA CB 50 5C C1 11 A7 07 54 69 91 27 E6 83 5F 00 17 00 41 04 59 C3 79 25 5C 1C 95 23 31 0D 1F 97 8B C8 5B AB 0F 3C 0D 41 15 0B 6F 1A 7C E2 91 4F 2E 28 51 A3 D4 02 DA 8B 8E D0 58 18 AE CF 14 02 AE E2 F4 C0 5C 43 55 34 11 8A F6 7B 97 F5 B3 F8 78 B0 18 09
	supported_versions	Tls1.3, Tls1.2
	signature_algs	ecdsa_secp256r1_sha256, ecdsa_secp384r1_sha384, ecdsa_secp521r1_sha512, rsa_pss_rsae_sha256, rsa_pss_rsae_sha384, rsa_pss_rsae_sha512, rsa_pkcs1_sha256, rsa_pkcs1_sha384, rsa_pkcs1_sha512, ecdsa_sha1, rsa_pkcs1_sha1
	psk_key_exchange_modes	01 01
	0x001c		40 01
	padding		136 null bytes
Ciphers: 
	[1301]	TLS_AES_128_GCM_SHA256
	[1303]	TLS_CHACHA20_POLY1305_SHA256
	[1302]	TLS_AES_256_GCM_SHA384
	[C02B]	TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
	[C02F]	TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
	[CCA9]	TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
	[CCA8]	TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
	[C02C]	TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
	[C030]	TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	[C00A]	TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
	[C009]	TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
	[C013]	TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
	[C014]	TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
	[009C]	TLS_RSA_WITH_AES_128_GCM_SHA256
	[009D]	TLS_RSA_WITH_AES_256_GCM_SHA384
	[002F]	TLS_RSA_WITH_AES_128_CBC_SHA
	[0035]	TLS_RSA_WITH_AES_256_CBC_SHA

Compression: 
	[00]	NO_COMPRESSION

If i press "Follow TCP stream" on Client Hello in Wireshark. Are these sites thinking i entered HTTP link or something?

...........cg....Tc....~.......o....@h....3..4.(.'.........9.3.....=.<.5./.,.+.$.#.



. .j.@.8.2.

.....H.........blueproject.ro.

...............

.....................................(<html><head><title>400 Bad Request</title></head><body>

<h2>HTTPS is required</h2>

<p>This is an SSL protected page, please use the HTTPS scheme instead of the plain HTTP scheme to access this URL.<br />

<blockquote>Hint: The URL should starts with <b>https</b>://</blockquote> </p>

<hr />

Powered By LiteSpeed Web Server<br />

<a href='http://www.litespeedtech.com'><i>http://www.litespeedtech.com</i></a>

</body></html>
Handshake Faliure from Wireshark
Transport Layer Security
    TLSv1.2 Record Layer: Alert (Level: Fatal, Description: Handshake Failure)
        Content Type: Alert (21)
        Version: TLS 1.2 (0x0303)
        Length: 2
        Alert Message
            Level: Fatal (2)
            Description: Handshake Failure (40)

Tried alternative HTTPS decrypters and they worked fine on the 2 examples above.

I wonder what's going on?

Thank you

Fiddler Classic
Nick Iliev
Telerik team
 answered on 06 Nov 2022
3 answers
8.5K+ views
Python HTTPS requests do not work while Fiddler is running

I tried running some requests in Python to see if they will appear in Fiddler

For a HTTP request, it worked with no problem:

However, trying to send a request over HTTPS results in long blocking and eventually fails. Nothing is logged to Fiddler, because no actual request was made. After 20-30 seconds, a long error is raised in Python:

urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='www.google.com', port=443): Max retries exceeded with url: /?id=1234567890 (Caused by ProxyError('Your proxy appears to only use HTTP and not HTTPS, try changing your proxy URL to be HTTP. See: https://urllib3.readthedocs.io/en/1.26.x/advanced-usage.html#https-proxy-error-http-proxy', SSLError(SSLError(1, '[SSL: WRONG_VERSION_NUMBER] wrong version number (_ssl.c:1129)'))))

What is causing Python to stop working (only while Fiddler is running)?  My current Fiddler version is v5.0.20204.45441 which is, I know, an old version. I trusted the root certificate, even installed it manually, and the HTTPS traffic from my browser is displayed normally as it should.

Fiddler Classic
Fiddler Everywhere
Noob Saibot
Top achievements
Rank 1
Iron
 updated answer on 06 Nov 2022
3 answers
618 views
Nothing capturing on Mac 10.15.6

I've just downloaded Fiddler Everywhere for the first time and installed on my relatively virgin Mac. I am logged in as adminstrator, and have enabled capture of https, but despite visiting several unsecure and secure urls within my browser, nothing is being captured in the Live traffic capturing tab (which is enabled). 

 

When viewing the network proxies tab, nothing changes between when Fiddler is running and not running, both HTTP and HTTPS checkboxes are unchecked with no server details. 

 

Is there an additional step to configure that I am missing? 

Fiddler Everywhere
Nick Iliev
Telerik team
 updated answer on 01 Nov 2022
0 answers
200 views
Critical error

When I use fiddler classic, response from https://ok.ru on my last laptop (Lenovo Legion Y520 Win11) is normal, but my new laptop (Asus ROG Strig G17 Win11) - have a problem with decode.

Error from Fiddler:

See the end of this message for details on invoking 
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.Exception: Brotli conversion failed
   at Fiddler.Utilities.BrotliExpand(Byte[] arrIn) in C:\Jenkins\Fiddler_Windows\workspace\FiddlerCore\FiddlerCore.Shared\Common\Core\Utilities.cs:line 2796
   at Standard.Transformer.Expand(ExpanderDelegate eD, Boolean bUpdateSizeLabel)
   at Standard.Transformer.doRaw(Boolean bUpdateSizeLabel)
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.RadioButton.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9093.0 built by: NET481REL1LAST_C
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/mscorlib.dll
----------------------------------------
Fiddler
    Assembly Version: 5.0.20211.51073
    Win32 Version: 5.0.20211.51073
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Fiddler.exe
----------------------------------------
System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9093.0 built by: NET481REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Core
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9093.0 built by: NET481REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------
System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9093.0 built by: NET481REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
Analytics
    Assembly Version: 1.0.20182.27266
    Win32 Version: 1.0.20182.27266
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Analytics.DLL
----------------------------------------
Microsoft.GeneratedCode
    Assembly Version: 1.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
System.ComponentModel.Composition
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.ComponentModel.Composition/v4.0_4.0.0.0__b77a5c561934e089/System.ComponentModel.Composition.dll
----------------------------------------
Telerik.NetworkConnections
    Assembly Version: 0.1.2.0
    Win32 Version: 0.1.2.0
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Telerik.NetworkConnections.DLL
----------------------------------------
Telerik.NetworkConnections.Windows
    Assembly Version: 0.1.2.0
    Win32 Version: 0.1.2.0
    CodeBase: file:///C:/USERS/VALDI/APPDATA/LOCAL/PROGRAMS/FIDDLER/PLUGINS/NETWORKCONNECTIONS/TELERIK.NETWORKCONNECTIONS.WINDOWS.DLL
----------------------------------------
MetadataViewProxies_13e3577d-0d9f-40cf-b9db-c5eff2edd807
    Assembly Version: 0.0.0.0
    Win32 Version: 4.8.9037.0
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.ComponentModel.Composition/v4.0_4.0.0.0__b77a5c561934e089/System.ComponentModel.Composition.dll
----------------------------------------
Standard
    Assembly Version: 2.6.2.0
    Win32 Version: 2.6.2.0
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Inspectors/Standard.dll
----------------------------------------
SyntaxView
    Assembly Version: 2.6.2.0
    Win32 Version: 2.6.2.0
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Inspectors/SyntaxView.dll
----------------------------------------
FiddlerOrchestra.Addon
    Assembly Version: 1.0.20202.16135
    Win32 Version: 1.0.20202.16135
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Scripts/FiddlerOrchestra.Addon.dll
----------------------------------------
FiddlerOrchestra.Connection
    Assembly Version: 1.0.20202.16135
    Win32 Version: 1.0.20202.16135
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Scripts/FiddlerOrchestra.Connection.dll
----------------------------------------
netstandard
    Assembly Version: 2.0.0.0
    Win32 Version: 4.8.9037.0
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/netstandard/v4.0_2.0.0.0__cc7b13ffcd2ddd51/netstandard.dll
----------------------------------------
FiddlerOrchestra.Protocol
    Assembly Version: 1.0.20202.16135
    Win32 Version: 1.0.20202.16135
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Scripts/FiddlerOrchestra.Protocol.dll
----------------------------------------
FiddlerOrchestra.Utilities
    Assembly Version: 1.0.20202.16135
    Win32 Version: 1.0.20202.16135
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Scripts/FiddlerOrchestra.Utilities.dll
----------------------------------------
RulesTab2
    Assembly Version: 2.6.2.0
    Win32 Version: 2.6.2.0
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Scripts/RulesTab2.dll
----------------------------------------
SimpleFilter
    Assembly Version: 2.6.2.0
    Win32 Version: 2.6.2.0
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Scripts/SimpleFilter.dll
----------------------------------------
Timeline
    Assembly Version: 2.6.0.3
    Win32 Version: 2.6.0.3
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Scripts/Timeline.dll
----------------------------------------
Microsoft.JScript
    Assembly Version: 10.0.0.0
    Win32 Version: 14.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Microsoft.JScript/v4.0_10.0.0.0__b03f5f7f11d50a3a/Microsoft.JScript.dll
----------------------------------------
System.Windows
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Windows/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Windows.dll
----------------------------------------
JScript Thunk Assembly
    Assembly Version: 0.0.0.0
    Win32 Version: 14.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Microsoft.JScript/v4.0_10.0.0.0__b03f5f7f11d50a3a/Microsoft.JScript.dll
----------------------------------------
Accessibility
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Accessibility/v4.0_4.0.0.0__b03f5f7f11d50a3a/Accessibility.dll
----------------------------------------
W2uBEJRg
    Assembly Version: 0.0.0.0
    Win32 Version: 14.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Microsoft.JScript/v4.0_10.0.0.0__b03f5f7f11d50a3a/Microsoft.JScript.dll
----------------------------------------
Microsoft.GeneratedCode
    Assembly Version: 1.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
GA.Analytics.Monitor
    Assembly Version: 1.0.20182.27266
    Win32 Version: 1.0.20182.27266
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/GA.Analytics.Monitor.DLL
----------------------------------------
System.Net.Http
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Net.Http/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Net.Http.dll
----------------------------------------
System.Security
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Security/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Security.dll
----------------------------------------
Newtonsoft.Json
    Assembly Version: 11.0.0.0
    Win32 Version: 11.0.2.21924
    CodeBase: file:///C:/Users/valdi/AppData/Local/Programs/Fiddler/Newtonsoft.Json.DLL
----------------------------------------
System.Numerics
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Numerics/v4.0_4.0.0.0__b77a5c561934e089/System.Numerics.dll
----------------------------------------
System.Runtime.Serialization
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Runtime.Serialization/v4.0_4.0.0.0__b77a5c561934e089/System.Runtime.Serialization.dll
----------------------------------------
System.Data
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9093.0 built by: NET481REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_64/System.Data/v4.0_4.0.0.0__b77a5c561934e089/System.Data.dll
----------------------------------------
Microsoft.mshtml
    Assembly Version: 7.0.3300.0
    Win32 Version: 7.0.3300.0
    CodeBase: file:///C:/WINDOWS/assembly/GAC/Microsoft.mshtml/7.0.3300.0__b03f5f7f11d50a3a/Microsoft.mshtml.dll
----------------------------------------
System.Web
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.9037.0 built by: NET481REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_64/System.Web/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Web.dll
----------------------------------------

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.

 

 

Click here don`t help me 

My settings

I check test version Fiddler Everywhere, and error have here.

 

Fiddler Classic
Vladyslav
Top achievements
Rank 1
 asked on 27 Oct 2022
1 answer
227 views
Overwrite a local file or delete it
I am using the 'File.AppendText' instruction to append data to a local file (in FiddlerScript).

Is there any way to clear the contents of the file before appending new data, such as overwriting the file or deleting it first? Is there any instruction for these tasks?

I just need to write data to a local file, and in case the file already exists, it should be overwritten.

Thank you!

Alex
Fiddler Classic
Nick Iliev
Telerik team
 answered on 27 Oct 2022
0 answers
241 views
I cannot decode https traffic from a specific ios application

There's a 3rd party ios app that i want to capture traffic from, and i'm not having any luck in doing so.  It is specifically the Twinkly app.  My web requests from the browser seem to be getting decoded and i did not expect the apple apps to be decoded, due to certificate pinning, but I really would like to get this working for a 3rd party app.  I installed a bouncy castle certificate and tried that, and I also set up a trial of Fiddler Everywhere and started over, with no luck.  Any ideas?  I am willing to jump through any kind of hoop necessary to get this to work, including jailbreaking the phone.

 

Fiddler Classic
Fiddler Everywhere
iOS
John
Top achievements
Rank 2
Iron
Iron
Veteran
 asked on 24 Oct 2022
1 answer
732 views
Option to make Fiddler respect browser's DNS-over-HTTPS (DoH)?

I know that Fiddler uses local DNS resolver as it didn't work on some test sites that only worked through DoH geobypassing proxy. Are there any trick/method to make Fiddler respect browsers DoH setting? If not, would you guys please consider adding it since DoH/DoT seems to be very useful/popular these days.

Here's some use case scenarios

  • You want to hide your DNS queries from your ISP while doing Fiddler session on a browser.
  • Your ISP filters your DNS (transparent DNS proxy, etc) and you want to debug sites that are blocked by your ISP with Fiddler.
  • You want to debug geo-blocked sites which can be bypassed by geo-bypassing DoH resolver.
  • and so on.

You can also add following to any of the scenarios above if we think alternative solutions like using Windows 10/11, configuring DoH on the router, using VPN, etc.

  • "you use an operating system that doesn't support configuring DoH/DoT"
  • "your ISP/Organization blocks VPN/proxies"
  • "your router doesn't support DoH/DoT"

BTW, I know Microsoft natively added DoH in Windows 10 more than a year ago, DoT to Windows 11 insider build a few months ago. I don't know if Fiddler works on them (works as in properly using DoH/DoT) as i don't use those OSes. I am curious to know about it though.

Anyways,

Here's quick guide to confirm that Fiddler/Firefox bypasses DNS-over-HTTPS just in case anyone wants to test.

Open Firefox (Use this guide for other browsers)

  1. Click the menu button Fx89menuButtonand select Settings.
  2. In the General panel, scroll down to Network Settings and click the Settings… button
  3. Check "Use system proxy settings"
  4. Scroll down to Enable DNS over HTTPS.
    • On: Select the Enable DNS over HTTPS checkbox.
      Check Custom and paste this server (this is DoH DNS resolver that blocks social media sites we are using for the test)
    • https://freedns.controld.com/p3
    • Press OK

  6. Open www.facebook.com and it should be blocked.

  7. Now open Fiddler and try to open www.facebook.com again on the browser. Facebook will work.



Fiddler Classic
Fiddler Everywhere
FiddlerCore
Nick Iliev
Telerik team
 answered on 24 Oct 2022
1 answer
232 views
How to use fiddlercore to capture ftp trrafic(file upload)?

i used these settings:

public static void StartupFiddlerCore()
        {
            // Build startup settings:
            var settings = new FiddlerCoreStartupSettingsBuilder()
                                //.CaptureLocalhostTraffic()
                                .MonitorAllConnections()
                                .CaptureFTP()
                                .DecryptSSL()
                                .RegisterAsSystemProxy()
                                .OptimizeThreadPool()
                                .Build();
            FiddlerApplication.Startup(settings);
            //FiddlerApplication.oProxy.Attach();

        }

 

when i use WinSCP and use the fiddlerCore's ftp proxy to connect ftp server, the fiddlerCore's ftp proxy did net capture the ftp traffic.

 

the picture is winscp's proxy setting.

FiddlerCore
Nick Iliev
Telerik team
 answered on 18 Oct 2022
0 answers
786 views
how to use fiddlerCore for capturing ftp traffic

I am using fiddlerCore to capture ftp traffic, and i used the "CaptureFTP()" setting and "RegisterAsSystemProxy()" setting.

But when i use Winscp application with fiddlerCore's proxy to connect ftp server,it did not work,and connect failed. 

how dose fiddlerCore's ftp proxy work? how to use it?

 

FiddlerCore
s
Top achievements
Rank 1
 asked on 17 Oct 2022
0 answers
252 views
Base64encoding request body

Hi,

I tried

static function OnBeforeRequest(oSession: Session) {
var arr: Byte[] = oSession.requestBodyBytes;
var istr: String = '';
istr =  Convert.ToBase64String(arr);

// ... do something with request body ...

oSession.RequestHeaders['Fiddler-Encoding'] = 'base64';
oSession.utilSetRequestBody(istr);
}

base on this article. Unfortunately this does not work. Any help appreciated.

Fiddler Classic
D
Top achievements
Rank 1
 asked on 17 Oct 2022
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