Upstream proxy error: "Gateway specified was unreachable and is being ignored"

3 posts, 0 answers
  1. Alex
    Alex avatar
    5 posts
    Member since:
    Oct 2014

    Posted 24 Oct 2014 Link to this post

    Hello.
    When specified upstream proxy becomes unavailable, Fiddler is showing this messages in "Tools > Fiddler Options > Gateway > Show Current Gateway Info" window:
    ---
    WARNING: HTTP Gateway specified was unreachable and is being ignored.
    WARNING: HTTPS Gateway specified was unreachable and is being ignored.
    WARNING: FTP Gateway specified was unreachable and is being ignored.
    ---
    As I understand, Fiddler is just skipping specified proxy and using system proxy instead.
    Is there a way to make Fiddler drop outgoing requests in case of invalid upstream proxy instead of forvarding 'em through the system proxy?
  2. Eric Lawrence
    Admin
    Eric Lawrence avatar
    833 posts

    Posted 24 Oct 2014 Link to this post

    Hello, Alex--

    Unfortunately, this question is quite complex.

    By default, Fiddler launches and adopts the system's proxy settings as an upstream proxy. If a host:ip is configured in those settings but that host:ip are not reachable when Fiddler starts, Fiddler ignores the proxy settings and defaults to sending traffic directly to the origin.

    If a host:ip proxy is initially responsive when Fiddler boots, but later becomes unresponsive, requests from Fiddler will fail until that proxy becomes responsive again.

    If Windows notifies Fiddler that the network has changed (e.g. you connected or disconnected for WiFi) Fiddler may redetect the upstream proxy settings.

    If you manually specify a proxy using the X-OverrideGateway flag on a Session, Fiddler 2.4.9.5 and earlier will fail the request if the proxy is unresponsive and the proxy uses SOCKS; if the proxy is unresponsive and is not SOCKS, the request will be sent direct. In Fiddler 2.4.9.6 and later (to be released shortly), Fiddler will fail the request if the X-OverrideGateway proxy is unresponsive whether it uses SOCKS or not.

    If you have a scenario where it makes sense for Fiddler to NOT ignore these proxy settings, please help explain it and I will consider adding a preference for that behavior in the next version.

    Regards,
    Eric Lawrence
    Telerik
     

    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. Alex
    Alex avatar
    5 posts
    Member since:
    Oct 2014

    Posted 25 Oct 2014 in reply to Eric Lawrence Link to this post

    Oh, everything is clearer now.)
    My wish is simple: I just want to make sure that all requests I'm sending to remote site are sent from one IP. I often use public proxies for testing, and they're quite unstable, you know.)
    As you've written, "If a host:ip proxy is initially responsive when Fiddler boots, but later becomes unresponsive, requests from Fiddler will fail until that proxy becomes responsive again". That sounds good enough for me.
    My only proposal is to add a MessageBox "gateway unreachable" just after hitting "OK" button in "Tools > Fiddler Options > Gateway" window, thus eliminating the need to check initial proxy state in "Proxy info" window or "Log" tab. But I don't know whether other Fiddler users would like that idea, so maybe it's better to leave UI unchanged.)
    Thank you for the quick and useful reply!
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