Certain traffic very slow to connect

[Toby]

Hi,

Recently, when running Fiddler, my browser is slow to complete requests on certain servers; averaging 20-40 seconds per request.

Chrome shows "Waiting for proxy tunnel", and I can see in the Fiddler Statistics, it says: 

TCP/IP Connect: 42039ms

I'm doing local development on Visual Studio, and the local requests are fast, but the CDN's make every page load take about 40 seconds.  And regular browser use typically takes that long too.  Not every site, probably 50%.  

I uninstalled (and wiped setting) and reinstalled which didn't help.  I also turned off "Capture HTTPS CONNECTs" which didn't do anything either.

Any help would be appreciated.  I love the tool and rely on it... but it's unusable for me right now.

Thanks,

Toby

[Tsviatko Yovtchev]

Hello,

Do you have any idea what triggered this? Fiddler update, OS update, etc.? 

What OS is that? Do you have a large number of sessions in Fiddler sessions list when this happens? Is the "Enable IPv6" option on or off? Does flipping it affect your problem?

Regards,
Tsviatko Yovtchev
Telerik by Progress

[Toby]

Hi Tsviatko,

Having the "Enable IPv6" option on was was definitely the problem, thanks for that!  Flipping that setting on and off (and restarting Fiddler) causes or fixes the 40 second load problem every time.

I'm on Windows 10, and it happens whenever Fiddler runs regardless of how long it's been on. If there's anything else I can do to help find the root of the problem, just let me know.

Otherwise, thanks for you help!

Toby

[Felix]

Thank you!

[Toby]

Oh, and I can't say what exactly triggered it, it's been happening for a couple months -- so I can't pinpoint when exactly it happened.  Sorry