DNS resolving fails after adding usb wifi dongle

[Vincent Gerris]

I noticed when a USB wifi dongle is plugged in and I disconnect the builtin one (Ubuntu 16.10), that resolving of DNS didn't work anymore.

I could ping for example google.nl on IP, but not resolve the name.

After some searching I found the issue seems to be caused by dnsmasq or systemd-resolved, the first being the most likely.

I disabled dnsmasq in NetworkManager and restarted it and stopped dnsmasq and everything works as expected.

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: dnsmasq 2.76-4
ProcVersionSignature: Ubuntu 4.8.0-30.32-generic 4.8.6
Uname: Linux 4.8.6-byt-freeze-fix x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.3-0ubuntu8.2
Architecture: amd64
CurrentDesktop: Unity
Date: Sun Dec 18 19:16:30 2016
InstallationDate: Installed on 2016-12-11 (7 days ago)
InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.2)
PackageArchitecture: all
SourcePackage: dnsmasq
UpgradeStatus: No upgrade log present (probably fresh install)