1169117 - Random 'Unable to find the proxy server' back again, but rarer

Status: UNCONFIRMED

(Core :: Networking: Proxy, defect, P3)

Description

[Ray Satiro]

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:41.0) Gecko/20100101 Firefox/41.0
Build ID: 20150525030205

Steps to reproduce:

Normal web surfing. I click to open a link in a tab or type something in to the search box.

Manual proxy configuration,
localhost 8888 for all protocols
No proxy for localhost, 127.0.0.1

This is too rare I'm not going to be able to get a regression window. The last time I saw it was a week ago.


Actual results:

Unable to find the proxy server

I am using the web debugging proxy Fiddler v4.5.1.0 and I can see nothing in its activity to indicate a connection when this happens. 

Also see bug #1101776 and bug #1123324. Gijs said open a new bug.



Expected results:

.

Comment 1

[Dragana Damjanovic [:dragana]]

https://bugzilla.mozilla.org/show_bug.cgi?id=1123324#c81

It has never happened before 12.5. and it happened couple of times after 12.5?

It is probably problem with DNS resolution. After looking a bit into change set  there is my patch that prevents retry to connect if we are offline.
Can it be that network went offline for short time?

What is the value of preference disableIPv6?

Comment 2

[Ray Satiro]

(In reply to Dragana Damjanovic [:dragana] from comment #1)
> https://bugzilla.mozilla.org/show_bug.cgi?id=1123324#c81
> 
> It has never happened before 12.5. and it happened couple of times after
> 12.5?

If you are referring to the date, then yes. 20150510030207 as far as I know was fine. I use Nightly regularly so I can assert prior builds were fine as well. This is an rare issue so it's possible it was in builds before 20150512030215 but only after my upgrade did I first encounter it again. 

> It is probably problem with DNS resolution. After looking a bit into change
> set  there is my patch that prevents retry to connect if we are offline.
> Can it be that network went offline for short time?

Nope the network is not offline. I've seen it twice today, actually. I can just click try again and the page will load. It's sporadic and rare. I don't know why I've seen it twice today, that's a lot. I do have a lot of tabs open at the moment, all e10s.

I checked in Fiddler and went through the log (in addition to the live activity which I usually check) because sometimes Firefox will connect but not make a request and the log will say something like:
<timestamp> No HTTP request was received from Firefox new client socket, port 123.
But in these cases there aren't entries that match around the time I see the Unable to connect to proxy message. So I'm pretty sure Firefox isn't making the connection at all. I can't Wireshark localhost so I can't say for certain.

> What is the value of preference disableIPv6?

network.dns.disableIPv6 = false

Comment 3

[Ray Satiro]

Just saw it again.

Version 	41.0a1
Build ID 	20150613030206

Comment 4

[Ray Satiro]

Just saw this again. I'm using build ec77f5c19262 20150811011940 42.0a1

Comment 5

[Ray Satiro]

Saw it again

Version 	43.0a1
Build ID 	20150909030223

Comment 6

[Ray Satiro]

I've seen it about a dozen times since this morning.

Version 	43.0a1
Build ID 	20150921030204

Comment 7

[Ray Satiro]

Just saw it, this time in Aurora. Proxy is set to localhost 8888.

Version 	52.0a2
Build ID 	20170118004007

Comment 8

[Firefox Bug Husbandry Bot]

Bulk change to priority: https://bugzilla.mozilla.org/show_bug.cgi?id=1399258

Comment 9

[Firefox Bug Husbandry Bot]

Bulk change to priority: https://bugzilla.mozilla.org/show_bug.cgi?id=1399258

Comment 10

[BMO Automation]

Moving bug to Core/Networking: Proxy.