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Unwanted background download activity

  • 20 risposte
  • 12 hanno questo problema
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  • Ultima risposta di teleguy

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I think the problem started about one week ago when I upgraded to Firefox 28, at least I didn't notice this behavior before.

I'm using the addon Flashgot and the Free Download Manager to manage my downloads. However recently with certain servers (which I had been using regularly for years without issue) FDM would start the download but it would sit at 0% for a while and then just switch to pause on it's own. I got a message that's because the server only allows one download at a time and there was already a download going on which I didn't know anything about. I also noticed that even the servers that worked were downloading a lot slower than they did usually and web usage in general was slow. I checked what was going on with a program called Netbalancer which showed that Firefox was constantly using up lots of bandwidth even though there were no webpages or videos loading and there was nothing showing up in the integrated download manager. I tried to close Firefox but that didn't fix it either. The same amount of bandwidth was being used now listed by Netbalancer as Service Traffic.

That happens every time I download anything on the web. As soon as the download dialogue window comes up Firefox apparently already starts downloading the file in the background even if I decide to just close the window or use FDM instead. It doesn't show up in Firefox's download window and there is no way to stop the download other than doing a reboot or waiting till Firefox has finished downloading the file even if it takes several hours!

So far I've tried upgrading to Firefox 29, downgrading to 21 which I used before, deleting my Profile, doing a clean install of 21 and checking my system for malware with several tools but nothing helped. I also tried downloading the same files with Internet Explorer+FDM and it worked without problems.

Soluzione scelta

Just found this topic: http://forums.avg.com/us-en/avg-forums?sec=thread&act=show&id=242984

turned off AVG and it looks like the problem is fixed.

Quote: "While building a simple Python/Flask sse streaming server, I found an issue related to firefox closing connections. It turns out the problem is caused by AVG 2014 surf-shield.

The full problem is stated in this post on StackOverflow: http://stackoverflow.com/questions/23580395/flask-sse-stream-not-terminated-after-firefox-disconnects. The main point is that, when surf-shield is on, at the moment firefox disconnects from the server, either by closing the tab or by reloading the page, the TCP disconnection sequece is not finished correctly, leaving the connection open. The TCP status of the Firefox side hangs in FIN_WAIT2, while the server side hangs in CLOSE_WAIT. This leads to a significant waste of resources, since the streaming threads keep running on the server-side. This has been verified on multiple machines, and is not a problem when either another anti-virus system is used or surf-shield is disabled. Other browsers don't seem to be influenced either.

If this is indeed a bug in AVG surf-shield, maybe this is something worth fixing. I don't know to which extent this generalizes to all servers, but if it does, this might cause some significant issues. "

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Tutte le risposte (20)

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I think Firefox has always started downloading in the background before and during the presentation of the Open/Save/Cancel dialog, but it should stop if you cancel. I don't know why it would continue.

In case one of your extensions is involved, could you test the download in Firefox's Safe Mode? That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Troubleshoot Firefox issues using Safe Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled (Flash and other plugins still run)

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

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Thanks for your reply. It does the same thing in Safe Mode.

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Is there any way to peer inside "Service Traffic" to get a better idea of what that is? Usually users complain that all downloads are terminated when they exit Firefox, so I'm puzzled by this.

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Yes, I found a few forum posts from people who had a problem similar to mine . They mentioned using Windows Resource Monitor and XfastLan. I tried both tools and both say the network activity is caused by firefox.exe even with Firefox closed.

XFastLan also shows what IP each process is connected to. I started a download with FDM and as you can see Firefox is also downloading from the same server.

Modificato da teleguy il

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I don't know how Windows' task manager can have the firefox.exe process running and not running at the same time. If you use Process Explorer, does it show that another owns firefox.exe as a child?

http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx

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Ok, you can forget about Resource Monitor. Looks like it doesn't just show current but also past activity.

However XFastLan seems to update in realtime.

As for Process Explorer I can no longer find the firefox.exe process after closing Firefox.

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Update: I'm totally puzzled. Now Internet Explorer started acting exactly the same.

Moreover when I got a SSD and installed Windows 7 I kept my old Windows 7 installation on another harddrive as a backup OS but haven't touched it in ages but that OS is somehow also affected.

I also found out it's somewhat dependent on the file. For example with this file

https://docs.google.com/uc?id=0B5qGbn3OCAd8WXViQkpUa2F6aEU&export=download

Firefox behaves like it should. But when I try to download this file

http://www.mediafire.com/download/rb4iqf555iakxbt/Elemental.rar

Firefox always acts up.

I'm almost resigned to bring my PC to the repairshop unless somebody has any more ideas.

Edit: Strange. IE is completely fine again.

Modificato da teleguy il

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I looked up XFast LAN to see whether I could use it for some testing, but it seems to be a feature of some systems, not a download I can get for mine.

One part of the description intrigued me, the claim that "Traffic Shaping allows you to watch YouTube HD videos and download files simultaneously. You will never have to wait for a long time for anything to load again." (ASRock Page) Is it possible that this feature is modifying how Firefox normally handles downloads?

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No, I only installed XFastLan after I noticed the problem.

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I made a tiny bit of progress. It turns out Firefox works properly if I start Windows in safe mode.

I thought that could mean that the problem was caused by a different application so I removed every autostart entry from Msconfig but the bug was still there. Then I also disabled every non Microsoft service but that didn't help either. Finally I selected "Load only basic devices and services" however that was also useless. Don't know where to go from here.

PS: How exactly does this support system work? What happens if nobody posts a solution to this question?

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I came upon a post that recommended the tool TCPView. I've attached a screenshot. When I close Firefox all instances of firefox.exe disappear except one that is stuck in the state of "Fin_Wait2" which apparently means the server is waiting for Firefox to close the port?

TCPView is also able to manually close that connection, so at least a workaround exists.

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This support forum doesn't have formal ticket ownership, so if no one can solve it, the next step is to file a bug.

Let me see whether I can replicate it and watch it in TCPview. However, with my current schedule, it probably will take a few days.

Are there particular sites or kinds of media which cause this problem? We should identify "steps to reproduce" (STR) since those will be needed for a bug filing.

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This file always causes the issue. http://www.mediafire.com/download/rb4iqf555iakxbt/Elemental.rar I think it has to do with the size of the file. Smaller files around 200 MB or less seem to be ok.

I had already tried to reproduce that bug on a different system with XP but it didn't occur there.

Edit: Not related to filesize after all. Just downloaded a 1 GB+ file without triggering a Fin_Wait2 state. File type doesn't seem to matter either. I guess it could be dependent on the server?

Modificato da teleguy il

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Soluzione scelta

Just found this topic: http://forums.avg.com/us-en/avg-forums?sec=thread&act=show&id=242984

turned off AVG and it looks like the problem is fixed.

Quote: "While building a simple Python/Flask sse streaming server, I found an issue related to firefox closing connections. It turns out the problem is caused by AVG 2014 surf-shield.

The full problem is stated in this post on StackOverflow: http://stackoverflow.com/questions/23580395/flask-sse-stream-not-terminated-after-firefox-disconnects. The main point is that, when surf-shield is on, at the moment firefox disconnects from the server, either by closing the tab or by reloading the page, the TCP disconnection sequece is not finished correctly, leaving the connection open. The TCP status of the Firefox side hangs in FIN_WAIT2, while the server side hangs in CLOSE_WAIT. This leads to a significant waste of resources, since the streaming threads keep running on the server-side. This has been verified on multiple machines, and is not a problem when either another anti-virus system is used or surf-shield is disabled. Other browsers don't seem to be influenced either.

If this is indeed a bug in AVG surf-shield, maybe this is something worth fixing. I don't know to which extent this generalizes to all servers, but if it does, this might cause some significant issues. "

Modificato da teleguy il

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Wow, great work!

I found a related report on AVG's forums, but AVG didn't really respond: Bandwidth Monitoring Data Artificially Increased By Surf Shield | AVG Forums.

Another user reported a seemingly similar issue on Chrome that AVG has recognized as a bug:

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Let's hope AVG provides a fix soon. I don't think it's really a good idea to use the web with surf shield turned off, especially when downloading files.

Can the Firefox developers do anything about it? Firefox seems to be affected a lot more by this bug than IE for instance.

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Is Surf Shield an extension (listed on the Firefox Add-ons page in the Extensions category)? Some extensions can be unpacked and examined to see how they interact with Firefox and better understand how the communication between them is failing.

Because I have other (non-free) security software, unfortunately I can't try out AVG myself without a lot of disruption.

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No, it's completely separate from Firefox.

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Does Surf Shield set up as a proxy? Perhaps there is some way that browsers and proxies communicate that is not working in this case. It is well out of my area of expertise...

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I don't think so.