On my computer I have dual boot Win 7 and Xubuntu 14.04 64-bit. Tonight I switched over to Xubuntu to work on something. When I fired up Firefox it acted like I didn't have an internet connection. Dropbox wouldn't connect either, however Spotify would play.
I am hardwired to my router. I checked UFW and found a whole slew of ports that said were being used by dnsmaq. I was doing some port forwarding yesterday and these ports with dnsmasq were not there.
I fired up my laptop which is connected via wireless thinking maybe I could use it to look for a solution online. It showed the same behavior. Web browsers acted like there wasn't an internet connection, Software Updater wouldn't download packages. It said to check my internet connection. I turned on my wireless hotspot on my phone and connected both computers to it. Connected to my phone I have internet access again.
I can't figure out what dnsmasq is doing or if it is conflicting with something. The only thing I can think of is that I configured network manager and my router to use OpenDNS servers. Could there be a conflict with that? When I'm running under Win 7 I have full internet access.