829823 - in Firefox 18.0, 'use system proxy settings' no longer works (Windows Vista)

Status: RESOLVED DUPLICATE of bug 828202

(Firefox :: Untriaged, defect)

Description

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Attachment: proxy.pac

User Agent: Mozilla/5.0 (Windows NT 6.0; rv:18.0) Gecko/20100101 Firefox/18.0
Build ID: 20130104151925

Steps to reproduce:

After installing Firefox 18.0, browser can no longer access internet while 'use system proxy settings' is selected -- in my configuration those settings specify a proxy.pac file


Actual results:

My Windows Vista system proxy settings were and still are set as follows, as displayed in the IE 'Internet Settings/LAN settings' dialog box:

(checked) Use automatic configuration script

(address) file://C:/Program Files/Samizdat/Agent/proxy.pac

the above URL is present in Windows registry 'Internet Settings\AutoConfigUrl' field

the proxy.pac file contains:

function FindProxyForURL(url, host)
{
   return "PROXY 127.0.0.1:8080; DIRECT";
}

both IE and Chrome respect this setting and correctly connect to the internet through the proxy when it is running, and fall back to a DIRECT connection when the proxy is not running

Firefox used to do so also, when 'use system proxy settings' was selected, prior to 18.0, but with 18.0 it will not connect to the internet at all with that selection, whether the proxy is running or not


Expected results:

Firefox 18.0 behavior should not have changed from the previous version

Firefox should use the proxy.pac file correctly when 'use system proxy settings' is selected, and should be able to connect to the internet using it

Workaround: select 'Automatic Proxy Configuration URL' and enter the above URL. Or select 'no proxy'. Firefox will connect to the internet in either of these modes, but it will NOT do so in 'use system proxy settings' mode (as it used to do prior to 18.0).

Comment 1

[Matthias Versen [:Matti]]

Thank you for the very good bug report.
This should be a dupe of bug 828202 and Mozilla will probably do a 18.0.1 release for this and 2 other issues in the 18.0 release