Capturing HTTPS causes eventual loss of internet connectivity

3 posts, 0 answers
  1. Matthias
    Matthias avatar
    2 posts
    Member since:
    Sep 2014

    Posted 04 Sep 2014 Link to this post

    I use Fiddler a lot to debug an application, and Fiddler Core for my own application. Both have the problem that when I start capturing and decoding HTTPS traffic with the fiddler certificate that eventually (hours to days) my PC has no internet connection whatsoever. My browsers report that DNS lookups failed, Chrome sometimes says "ERR_NAME_RESOLUTION_FAILED", and so on. The only solution to restore connectivity is to stop capturing https, remove the certs, and restart the PC. There are also less severe cases when I only lose internet when I close Fiddler. All of this is bothersome for me and unacceptable for my app. Is there anything I'm doing wrong? I leave the default options in Fiddler except for the https capturing and decrypting. I use an auto-updated win 8 and auto-updated fiddler I am on a home LAN behind a router/modem.
  2. Eric Lawrence
    Eric Lawrence avatar
    833 posts

    Posted 05 Sep 2014 Link to this post

    Hi, Matthias--

    I run Fiddler 24/7 for weeks and have never seen any problem like the one you describe. 

    All of the errors you mention are errors that would be shown when the browser's DNS lookups fail; browsers do not use DNS when Fiddler or FiddlerCore are capturing their traffic, so your question is especially confusing.

    Is there some reason you believe this is related to HTTPS-- does the problem not occur if you don't enable decryption, for instance?

    In the failing scenario, if you go to a command line and type nslookup what happens?

    Eric Lawrence

    Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.

  3. Matthias
    Matthias avatar
    2 posts
    Member since:
    Sep 2014

    Posted 06 Sep 2014 Link to this post

    The problem has never happened without Fiddler capturing HTTPS, but that may have been coincidence, because I also leave it running for a long time, so any problem that occurs would occur with Fiddler running. I don't know about Fiddler running without HTTPS, since I always need the HTTPS decryption. I will try to recreate the problem without HTTPS, and I will try to fix the problem when it occurs  without disabling HTTPS decryption. Maybe the problem is with my ISP or router having issues at times, I will try to find out.
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