Firefox starts in off-line mode

Question

I had some problems with Ubuntu previously. Here and here are related questions. After solving them I noticed that after I start computer, Firefox starts in work off-line mode. Over the time I've had similar problems with some other applications too, but only Firefox comes to mind right now. the problem is that my network connection seems to be working fine.
Even when I started Firefox in order to type this question, I was downloading updates from apt-get. When I typed http://superuser.com, Firefox told me that there I need to connect to Internet and switch to on-line mode.

Answer 1

Check this out: http://kb.mozillazine.org/Toolkit.networkmanager.disable You can find this pref and change its value by typing about:config in the address bar.