Fiddler does not capture https (some sites)

[Risto]

I have Windows 7 6bit. Fiddler 2 fresh install, no scripts, filters are off, https capturing/decryption enabled, certificate exported and installed/stored under Trusted Root Certification Authorities. Tried with Chrome and Firefox.

 When I browse  2 sites from internet that both use https and are constantly communicating with fresh data (page itself is not fully reloaded, only data within) probably with jQuery/API in JSON/XML format from the server then one site data communication is captured and the other not. I captured same site data communication over the year ago with success and without any tricks (except allowing https capture/decryption in Fiddler). From visible side the site has not changed.

 If anyone interested testing then:

https://ee.olybet.com/en/Sports/?method=PreMatch

go to LIVEBET, pick one ongoing event and wait the data communication (red/green arrows will appear)

I am very thankful for any hint.

[Ankit]

Hi Risto,

 I am facing a similar problem. Are you using Fiddler4.6.0.2?

[Risto]

I tried both 4.6.0.2 and 2.6.0.2

[Eric Lawrence]

Hi, Risto--

Unfortunately, that site cannot be loaded from the United States. If you send us a SAZ file (File > Save All Sessions, Help > Send Feedback) we may be able to look at your data capture to troubleshoot further.

Regards,
Eric Lawrence
Telerik

[Risto]

Eric helped me out. I had Firefox set on using system proxy. This site probably needed 127.0.0.1:8888. 

[Eric Lawrence]

Thanks for letting me check this out on your computer!

The root cause of this problem was that Firefox was set to Use System Proxy instead of having its proxy settings pointed directly at Fiddler. In general this works just fine, but in Firefox it has one peculiar quirk-- Firefox looks at the SOCKS proxy setting when deciding what proxy to use for WebSockets, and since the system's SOCKS proxy was not set, the WebSocket connection went direct and bypassed Fiddler.

Both IE and Chrome will correctly use the system's HTTPS proxy setting rather than the SOCKS proxy setting.

Adjusting the Firefox proxy settings to manual allowed us to see the WebSocket connection in question.

Regards,
Eric Lawrence
Telerik

[Risto]

Thank you Eric for showing me that Fiddler2 can capture those HTTPS sessions. But there's some more magic in the process and I am lost again. Firefox proxy is now set to Fiddler (pages complained about proxy when Fiddler was not running). Fiddler STREAM option is on, Firefox is restarted. Now I see from browser that page constantly receives data from internet but still I cannot see those sessions. 

[Risto]

My bad. I had to double click in sessions window at the "initial WebSocket entry". The data collection appears then under websocket tab.