I have an internet connection that works through a proxy that requires username & password. After online upgrade to 14.04 from 12.04, I am unable to connect to internet, pinging to popular sites doesn't work. However, I am able to ping to local addresses in my office network. I shall post any more info if needed. I am a networking noob and didn't fiddle with anything in my network settings yet.
Use the following command in terminal(Ctrl+Alt+T)to fix this issue.