Chrome intermittently unable to download PAC file, must be reset to default settings to resolve.
Reported by
grobinso...@googlemail.com,
Nov 23 2017
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Issue description
Chrome Version : 62.0.3202.94
URLs (if applicable) :
Other browsers tested:
Add OK or FAIL, along with the version, after other browsers where you
have tested this issue:
Safari: N/A
Firefox: OK
Edge: OK
What steps will reproduce the problem?
(1) Configure Chrome via AD group policy to use a PAC file to access internet via Bluecoat proxy servers
(2) Users occasionally experience failure to connect to internet in Chrome but other browsers on the same PC still work fine.
(3)
What is the expected result?
We use a PAC file distributed through Active Directory to tell our browsers to use our proxy servers. Our firewall is configured to block any direct connections to the internet from users PC's, so browsers must use a proxy server to access the internet.
This generally works fine, however we get occasional reports of Chrome displaying error “This site can’t be reached, the site took too long to respond, ERR_CONNECTION_TIMED_OUT ” when accessing the web.
In "chrome://net-internals/proxyservice.config#proxy” the effective proxy settings shows “Use DIRECT connections”
In "chrome://net-internals/proxyservice.config#events" the first entry shows a URL_Request for "https://clients4.google.com/chrome-sync/experimentstatus" with net_error="118 ERR_CONNECTION_TIMED_OUT"
When this problem is occuring if you try to manually download our PAC file in Chrome from that PC it will fail to download [no error, it just times out], however the PC can still manually download the PAC file in IE, and other PC’s running Chrome are still able to download the PAC file manually, so the problem is local to the Chrome browser on that specific PC.
What happens instead?
Please provide any additional information below. Attach a screenshot if
possible.
The only solution we have found is to reset Chrome to default settings and restart the browser, after which it works fine again. Some users experience this problem only once, others keep getting the same problem repeatedly over a period of weeks.
Could you please advise how we can resolve this problem or help troubleshoot it further?
,
Nov 27 2017
Unable to triage this issue from TE-End, CC'ing dev for further triage.
,
Nov 27 2017
Can you try starting the browser with the --log-net-log=<somefile> flag to be able to capture net logs of the startup when this issue is exhibited. This should allow you to see what error is Chrome encountering when trying to download the PAC file. If needed you can then share the logs here for further analysis. Usually the logs are anonymized to good extent but you should still decide for yourself if you need to further clear them before uploading.
,
Nov 27 2017
,
Nov 28 2017
The "PROXY_SCRIPT_DECIDER_FETCH_PAC_SCRIPT" shows "net_error = -102 (ERR_CONNECTION_REFUSED)"
,
Nov 28 2017
Thank you for providing more feedback. Adding requester "manoranjanr@chromium.org" to the cc list and removing "Needs-Feedback" label. For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
,
Nov 29 2017
Hmm any software that might be interfering? Firewalls/AV etc? Flaky network connection (bad cable/driver)?
,
Nov 29 2017
There are no firewalls between the PC's and the server that hosts the PAC file, and it seems to occur randomly on various different PC's. Whilst the problem is occuring on a PC you can still manually donwload the PAC file on that PC using Internet Explorer, and other PC's can still manually download the PAC file using Chrome. Resetting Chrome to defaults and restarting the browser always resolves the issue, so the problem appears to be local to Chrome.
,
Nov 29 2017
Ok. I am not deeply aware of the proxy handling code in Chrome but I wonder if it could have a bug where it tries to use a cached proxy value to fetch the pac file or some such. Can the pac file be reached even _through_ the proxy itself? Adding the network/proxy label for visibility for the right people.
,
Nov 29 2017
The PAC file is configured so that any traffic to an internal server goes direct. Our proxy server categorises our PAC file URL in the "Health" category, so if for some reason Chrome was trying to access the PAC file via the proxy server this should still work as all users are permitted to view the "Health" category.
,
Nov 29 2017
In response to comment #9: We won't use the proxy to download the PAC file itself, though we if you manually try to load it directly we do for that request. I don't think we can make any progress here without a net log of this happening, as requested in comment #3.
,
Dec 8 2017
I'm closing this for lack of activity. Please file a new bug if you can provide the information requested. |
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Comment 1 by krajshree@chromium.org
, Nov 24 2017Components: Enterprise
Labels: TE-NeedsTriageFromHYD Needs-Triage-M62