Did the suggestions here help you? I have the same problem you described. I can add a little texture to it as well. Oddly enough even though browsers will stop working instantly returning "ERR_CONNECTION_FAILED" on the command line pings, and DNS lookups continue to work perfectly. I also work with VMWare Workstation extensively, and even after the browsers in my Host have stopped working my network continues to work perfectly within the Guest (Ubuntu) environment.