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Firefox proxy problem.

New User

Firefox proxy problem.

I've had this weired problem with Firefox. While i was browsing an error message come up saying cannot connect to the website... check proxy settings. In other tabs there were some chinese sentence saying basically the same thing. Other browsers worked fine. So i did a research and found this forum: which suggested to set the proxy settings to no proxy. I did that and worked but when i closed and restarted firefox again the problem was still persisted. So i tried again but this time at the proxyx settings tab by clicking to the network tab the poping up window was not the same instead it was a window with some autoproxy setting window so i was not be able to set it to "no proxy" again. And also with the previous attempt i found out that there was some weired proxy set that i have never seen: I went back to the forum for more research and i found that i should disable some add-ons so i did disable foxy proxy. The problem seems to be gone now however my question is: 1. What's changed my proxy settings? 2. Can it be a trojan, virus or malware? 3. If it is one of them How is it possible, when i'm using ubuntu (13.04)? 4. How can i comfirm this?

Thanks for the help

Grand Master

Re: Firefox proxy problem.


Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

  • You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
  • Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Thank you.

SUMO Contributor

Re: Firefox proxy problem.

Some preferences can be reset at startup by an extension or by a setting is an external file such as user.js. The suggestion by colbabomb will help you rule out an extension. To hunt down a user.js file, try this article: How to fix preferences that won't save.

External malware also is a possibility. You may want to run some supplemental scans. These three tools are highly regarded (and free):

Edit: Oops, don't know of security security scanners for Linux, sorry.

Site Moderator

Re: Firefox proxy problem.

This is likely caused by an extension, possibly Proxy List 2.2 that shows in the system details list.

New User

Re: Firefox proxy problem.

Hi Guys, Thanks for your responses.

To colbabomb: I was in safe mode when i set connection settings to "no proxy" in: Edit->Preferences->Advanced->Network->Settings->Conection Settings. It worked, I could browse in safe mode but when i restarted firefox the problem came back.

To All of you: At the moment with Foxy Proxy disabled everything seems to be working fine i can browse without any problem. I just want to find out, what can change your proxy setting and reset a new proxy for you that you have know idea about while you are just surfing on the internet. It was not a new update of the firefox or newly installed add-on it just came out of the blue. That is why i'm worried about some malicious threat or maybe a bug. On linux i have never had a virus or something. Is there any at all for Linux which causes similar symptoms.

If you need anymore information about a file, crash log or something let me know. Other than that I can live without Foxyproxy. I just don want others to be effected by this problem.


Grand Master

Re: Firefox proxy problem.


The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions (you have to manually reinstall them after), Open websites, and some Preferences.

To Reset Firefox do the following:

  1. Go to Firefox > Help > Troubleshooting Information.
  2. Click the "Reset Firefox" button.
  3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
  4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

Thank you.