I am running Mint 18 (I had the same problem on Ubuntu 14.04 – so I assume this is a general Ubuntu problem) where my internet connection goes out intermittently.
It stays connected to the wifi, but suddenly it cannot resolve any addresses. I have to turn wifi off and on again to reconnect (which is a pain since this is my media server)
I tried tailing the system log and saw something about resolver waking up- but wasn’t sure if that was something to do with it or what it meant- couldn’t find anything.
Any suggestions would be greatly appreciated.