When there's a HAR file with h3 entries, they are either misinterpreted or ignored.

I know how to fix it both in the importer/exporter DLL and in Fiddler.exe.

I can submit a correction.

For now fiddler just have filter, and it not ignore traffic. Filter just hiding it.

Also Fiddler have option "Capture/Dont capture traffic" via menu File or F12. but it general for all. Also this option NOT work while the target app still use fiddler proxy.

My example problem :

I am using Nox to test MyDownloader app, while apk connect internet or requesting web data its ok to proxified by fiddler. But when I start downloading, the file is downloaded first to Fiddler cache until complete. after complete then fiddler continue request with that file response. That the problem. This also applied to all request in my PC. No problem if size just 20MB. But above 100M, 500MB, 1GB, sometime it make fiddler hang.

Also when i download file, then cancel it, fiddler still download file until complete. So to cancel that in fiddler, i need to disconnect it first.

For now, to bypass my problem i also using Proxi*fi*er filter to selecting mimetype.

Hello! The problem is described on this link: stackoverflow

 Please add in Filter -  feature block named "Request Body" with options "Show only if request body contains", "Hide only if request body contains"

Hi there, what's the correct way to call:

JSON.stringify({});

JSON.parse("{}");

after calling these JSON methods, fiddler says:

Variable 'JSON' has not been declared

cheers,

David

I want to capture the traffic from Android Phone, and already install Root Certificate as 'System Trusted Credintials' in /system/etc/security/cacerts (renamed like '269953fb.0' by md5).

Accessing the https page, It seems to behave well in a normal application and other browser (like XBrowser, a tiny volume browser, only 1.01MB) ,and which proves that the certificate is installed correctly, but in Chrome it prompts 'NET:ERR_CERT_AUTHORITY_INVALID'. As shown, it seems that Chrome does not associate the web certificate returned by Fiddler with the root certificate already installed on the system, but I use the same installation method in Charles, it behaves well and can browse https pages normally, it seems that Charles generates a different certificate than Fiddler? I used the command

'openssl x509 -inform der -text -in /mnt/d/Users/menEu/Desktop/FiddlerRoot.cer'

to see the difference and it doesn't seem to be a huge difference (but I'm not specialized in this area)

I've tried multiple allocation ratios and nothing solves the problem, the screen allocation ratio is 2560x1600.

Version Windows 10 Home Chinese
Version number 21H1
Installation Date ‎2021/‎12/‎25
OS Build 19043.1586
Experience Windows Feature Experience Pack 120.2212.4170.0

fiddler version :

Could you add 'search text' function to the websocket tab?

In the File > Export > Export Raw Files code, there's a "Skip non-HTTP/200 responses" option. This option is designed for dumping files (either media files or files to be replayed by the AutoResponder) to a folder.

For various reasons, clients and servers often will use Range requests for media downloads, meaning that the response code for a response might be HTTP/206 instead of HTTP/200, even if the full body is present.

To enhance the file exporter, the code should look at the Content-Range response header for a HTTP/206 response. If the header is of the format:

Content-Range: bytes 0-N/N+1

Then Fiddler should treat the response as a HTTP/200 and save the body to disk.

So far Fiddler says it can only import unencrypted sessions from PCAP files.

Various tools and libraries support the SSLKeylogfile environment variable and log the necessary keys.

You can either have them inside the pcapng file or in a seperate file.

It would be nice if Fiddler would accept an optional file with these keys and treated sessions with a suitable key as unencrypted.

This would make things a lot easier in the process.

Hi,

I have a connectivity issue when I run Fiddler (Progress Telerik Fiddler Web Debugger). I work behind a corporate proxy server and the server IP is changed every few hours. The change in IP is normally okay, but when I am running Fiddler with the 'Automatically Authenticate' option enabled, then Fiddler shows an error every time the proxy is changed; it shows a yellow error message suggesting "The system proxy was changed. Click to reenable capturing".

Clicking on the error in Fiddler works fine and it reconnects, but I find this frustrating because if i don't realise there was an error in fiddler and don't click it immediately then it affects my connectivity and some activities on my pc start to fail without me realising.

My suggestion is that you should let Fiddler auto-reconnect when this type of proxy change happens and when the 'Automatically Authenticate' option is enabled. I know it can't try to reconnect forever because it will cause an endless cycle for other people who have other types of proxy disconnects, but in my case it would be very helpful to let fiddler at least try once to auto reconnect (for me 1 retry is usually fine and Fiddler is able to connect to the new proxy address, but perhaps you can let the number of retries be a menu option so that users can set the number of retries that they want Fiddler to do after there was a proxy change or proxy error).

Thanks so much for your work, I really like Fiddler!

I hope you can bug fix this or add it as a feature, it will be very helpful!

Regards,

Eugene

This is a feature that's present in both the Firefox and Chrome dev tools, and it's incredibly useful. Fiddler is already great, and that would make it so much better :-)

This seems to happen a non-trivial number of times, and it causes clients and scenarios to fail in surprising ways.

When HTTPS decryption is enabled in Fiddler, Fiddler parses the ClientHello and ServerHello HTTPS messages to determine the supported ciphers and other information, including TLS Extensions.

Unfortunately, Fiddler's HTTPSMessages parsers have a bug whereby if the extensions are larger than the available data on the stream/pipe, reading of the extensions is skipped and misleading text suggesting that no extensions were sent is shown in the Inspectors. For instance, the current version of Chrome Canary sends ~1308 bytes of TLS extensions in the ClientHello, but only 908 bytes are available at the time that the message is read. Fiddler claims that the ClientHello contained no extensions. 

Instead of performing a single .Read() call and ignoring the result if the size is less than expected, Fiddler should continue to read the stream until the promised number of bytes have been read.

[This issue is similar to https://crbug.com/1028602#c2, although the implementation is obviously unrelated).

"Target Any Process" feature no longer working with Chrome. It used to work but no longer works specifically with Chrome. Still works with other processes. Capturing still works with Chrome as long as I am not using the "Target Any Process" feature.

The GetSupportedVersions function inside HTTPSUtilities has an off-by-one error in the parser that results in omitting the final value in the list.

Instead of code like this:

    for (int index = 1; index < arrSupported.Length - 2; index += 2)

the code should instead be:

    for (int index = 1; index <= arrSupported.Length - 2; index += 2)

It would be highly useful if there was a "URL splitter" tool added, perhaps as a drop-down entry in the TextWizard, which takes a long-form paramaterized URL and splits it into a line-separated list of individual parameters (and can go the opposite way direction as well).

The "WebForms" subpanel already does this, albeit there's no manual ability to choose what URLs this can be done to ...as far as I'm aware.

Precondition:

• Have a list of several AutoResponder rules.

Steps to reproduce:

• Select a rule in the list.
• Press the M hotkey to set a comment for the rule.
• Edit the comment.
• Save the comment by confirming with OK.

Expected result:

• The comment edit dialogue displays the current comment of the rule selected in the list.
• Confirming the dialogue updates the comment of the rule selected in the list with the text box content.
• The list selection does not change.

Actual result:

• The comment edit dialogue displays the current comment of the rule selected in the list (expected).
  
• As the edit dialogue opens, the selection in the AutoResponder list changes and a different rule is highlighted.
• Confirming the dialogue updates the comment of the newly selected rule, not the one the user manually selected and whose initial comment was shown in the edit dialogue.

Version: 5.0.20192.25091 (2019-06-04)
Platform: Windows 10 build 17134, .NET 4.7.1

Inside the Header inspector, you can add a header to a breakpointed response. The header editor offers templates. The "Set-Cookie" template for persistent cookies has an expiration date that seemed impossibly far in the future: June 2021.

Well, I may not have a flying car, but we're now living in a future beyond that imagined by the header inspector. We need to update to a later expiration date.

The bug I'm reporting is sometimes the Session.HostnameIs() will return true even if the supplied hostname does not match Session.hostname and a port was passed by the client in the Host header.

HostnameIs function is documented as "This method compares the supplied hostname to the hostname of the request, returning true if a case-insensitive match is found."

What I think is happening is that rather than use Session.hostname for comparison Fiddler instead uses the Session.host (ie what was passed by the client in the Host header) and if a port is present maybe it incorrectly extracts out the hostname. Here is an example that shows the bug and why I think that.

In OnBeforeRequest add this code, which should only show an alert box if the hostname is test:

		if(oSession.HostnameIs("test")) {
			FiddlerObject.alert(oSession.hostname);
		}

Now in a browser try going to http://t:81/ and you will see it shows the alert box, in other words a match. Why? Well, I will guess based on my testing that your code in HostnameIs gets the index of the colon in the host t:81, which is 1, and then compares only that number of characters. So it's doing whatever is the javascript equivalent of !strnicmp("t", "test", 1).

This manifests itself through CONNECT as well, and probably more likely, since the standard ports are used in the Host header (IE might be an exception to this). For example, let's say you go to https://t/ in Firefox or Chrome and HTTPS decrypt is enabled. The Host passed by the client for the CONNECT is t:443 and so it's the same problem, !strnicmp("t", "test", 1).

This is not a theoretical issue for me, I was testing something earlier today where I had to treat a hostname that ended in .co different from the same hostname that ended in .com and it turned out the test I was doing applied to both of them because of this bug.

https://twitter.com/ozziepeeps/status/1349126308454830082

Basically, the problem here is that if we're AutoAuthenticating when reissuing a request, we try to strip any default Auth header.

There's code that looks like

   if (theFlags.ContainsKey("x-AutoAuth") && newSession.requestHeaders["Authorization"].OICContains("NTLM") 

//... strip the header

The problem is that we should only be looking at the very first token of the Authorization header (e.g. before the first space). We should not search the whole header, because if the header is

    Authorization: Bearer BlahblahblahNtLMblahblah

we think it's an NTLM header and strip it.