I had a similar issue after upgrading from 15.04 to 15.10 yesterday I was loosing DNS resolution ramdomly few minutes after VM start
Mar 18 10:27:17 guillaume-box NetworkManager[885]: <info> DNS: starting dnsmasq... Mar 18 10:27:17 guillaume-box NetworkManager[885]: <warn> dnsmasq not available on the bus, can't update servers. Mar 18 10:27:17 guillaume-box NetworkManager[885]: <error> [1458293237.010557] [dns-manager/nm-dns-dnsmasq.c:387] update(): dnsmasq owner not found on bus: Could not get owner of name 'org.freedesktop.NetworkManager.dnsmasq': no such name Mar 18 10:27:17 guillaume-box NetworkManager[885]: <warn> DNS: plugin dnsmasq update failed Mar 18 10:27:17 guillaume-box NetworkManager[885]: <info> Writing DNS information to /sbin/resolvconf [...] Mar 18 10:27:17 guillaume-box dnsmasq[965]: DBus support enabled: connected to system bus Mar 18 10:27:17 guillaume-box dnsmasq[965]: warning: no upstream servers configured I was observing, dnsmaq process indeed running but not consistently resolving name requests. I was observing empty dnsmasq conf files: guillaume@guillaume-box:/etc/NetworkManager/dnsmasq.d$ ls -al total 8 drwxr-xr-x 2 root root 4096 avril 17 2015 . drwxr-xr-x 7 root root 4096 mars 17 23:11 .. guillaume@guillaume-box:/etc/NetworkManager/dnsmasq.d$ ls -al /var/run/NetworkManager/dnsmasq.conf -rw-r--r-- 1 root root 0 mars 18 10:27 /var/run/NetworkManager/dnsmasq.conf Whereas the network manager was properly displaying the DHCP provided DNS servers in the its UI. Trying to turn off and on network in the network manager did not solve the issue. I ended up turning off dnsmasq by eding /etc/NetworkManager/NetworkManager.conf and comment out the following line from dns=dnsmasq (as suggested into http://www.ubuntugeek.com/how-to-disable-dnsmasq-in-ubuntu-12-04precise.html) This seems to have worked around the issue. I understand the limitation of the workaround (disabling dnsmasq) is that I don't have anymore a local DNS cache, and only the 1st respondind DNS server is queried for address resolution. I ran into a reported bug (sorry I lost its reference) that claimed this to be a distribution upgrade problem, and was suggesting to uninstall dsnmaq and reinstall it. I haven't tried yet. Hope this helps narrowing this nasty bug which was quite time consuming to me. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/1048430 Title: "dnsmasq not available on the bus" Status in network-manager package in Ubuntu: Confirmed Bug description: Dnsmasq seems to be having some issues. This occurs whenever I try to connect to my wireless network; sometimes it only happens once, but sometimes the error loops for a while. Sep 9 17:43:51 bkerensa NetworkManager[935]: <info> DNS: starting dnsmasq... Sep 9 17:43:51 bkerensa NetworkManager[935]: <error> [1347237831.899067] [nm-dns-dnsmasq.c:390] update(): dnsmasq not available on the bus, can't update servers. Sep 9 17:43:51 bkerensa NetworkManager[935]: <error> [1347237831.899142] [nm-dns-dnsmasq.c:392] update(): dnsmasq owner not found on bus: Could not get owner of name 'org.freedesktop.NetworkManager.dnsmasq': no such name Sep 9 17:43:51 bkerensa NetworkManager[935]: <warn> DNS: plugin dnsmasq update failed Sep 9 17:43:51 bkerensa NetworkManager[935]: <info> ((null)): writing resolv.conf to /sbin/resolvconf ProblemType: Bug DistroRelease: Ubuntu 12.10 Package: dnsmasq (not installed) ProcVersionSignature: Ubuntu 3.5.0-13.14-generic 3.5.3 Uname: Linux 3.5.0-13-generic x86_64 ApportVersion: 2.5.1-0ubuntu7 Architecture: amd64 Date: Sun Sep 9 17:47:22 2012 EcryptfsInUse: Yes InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425) ProcEnviron: TERM=xterm PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: dnsmasq UpgradeStatus: Upgraded to quantal on 2012-08-08 (32 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1048430/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp