VPN Problems and Ubuntu: killing off the dnsmasq zombie

I’ve been having problems with VPN, DNS and Ubuntu for a year. But, I’m also pretty lazy when it comes to spending time on configuration. And configuring VPNs is like last on my list of ways I’d like to spend my time.

In short, I’d rather reboot than figure out exactly why my networking just stopped working.


Fortunately, I had an easy (for me) work-around for most of my VPN needs: use SSH and a jump-host for getting to servers. I found it annoying when I wanted to look at a website on protected network space, or had a service on an unusual port that I wanted to test things against. I would work around with SSH tunnels, or I would fire up my Mac, whose VPN settings worked flawlessly.

That all said, I thought today, a sunny, lovely fall day in Portland, I would fix my VPN.

And so, my buddy @uberj_ helped me get things sorted.

The root cause of all my VPN heartache was the dnsmasq daemon controlling my DNS. And, related, network-manager. There are a few places that document exactly how to disable dnsmasq

  • DNS in Ubuntu 12.04 http://www.stgraber.org/2012/02/24/dns-in-ubuntu-12-04/
  • Disabling dnsmasq as your local DNS server in Ubuntu http://mark.orbum.net/2012/05/14/disabling-dnsmasq-as-your-local-dns-server-in-ubuntu/

However, they leave out one important step: killing off the existing dnsmasq process. For the unlucky, restarting network-manager does not kill off dnsmasq.

So, to find and kill dnsmasq, do the following:

 sudo service network-manager stop
 kill `ps -C dnsmasq -o pid=`
 sudo service network-manager start

Then, start your VPN and check out the contents of the /etc/resolv.conf. If all went well, you’ve got nameserver addresses other than in the file.


Sadly, this was not the end of my story.

After a few minutes, NetworkManager started dnsmasq up again!

Zombie dnsmasq

So, like any reasonable sysadmin, I opened up the /etc/NetworkManager/NetworkManager.conf file, uncommented the dns=dnsmasq line, and replaced it with dns=/dev/null. My guess was that you can probably put just about anything other than dnsmasq into that line to permanently disable the plugin.

I ran sudo service network-manager restart, checked /etc/resolv.conf and felt pretty smug.

I tried also uninstalling dnsmasq-base package, but unfortunately that takes out a number of other packages I appear to need. So, I left /dev/null in my NetworkManager.conf, and updated this blog post.

But wait...

While editing this blog post, dnsmasq took over my DNS settings again.

A clue as to what was happening was in /var/log/syslog:

Oct 18 10:20:10 localhost dnsmasq[30535]: started, version 2.59 cache disabled
Oct 18 10:20:10 localhost dnsmasq[30535]: compile time options: IPv6 GNU-getopt DBus i18n DHCP TFTP conntrack IDN
Oct 18 10:20:10 localhost dnsmasq[30535]: DBus support enabled: connected to system bus
Oct 18 10:20:10 localhost dnsmasq[30535]: warning: no upstream servers configured

It turns out that dnsmasq was still getting revived by NetworkManager. Why NetworkManager doesn’t seem to care about configuration settings was beyond my willingness to investigate today. So, I did some more searching about truly killing of dnsmasq for good.

And I found this thread, and this sample configuration file. In the output for the dnsmasq process from ps:

nobody   30777 30759  0 10:21 ?        00:00:00 /usr/sbin/dnsmasq --no-resolv --keep-in-foreground --no-hosts --bind-interfaces --pid-file=/var/run/sendsigs.omit.d/network-manager.dnsmasq.pid --listen-address= --conf-file=/var/run/nm-dns-dnsmasq.conf --cache-size=0 --proxy-dnssec --enable-dbus --conf-dir=/etc/NetworkManager/dnsmasq.d

I dug into the thread, and the suggestion was to set port=0 in the config. I created a file called custom in /etc/NetworkManager/dnsmasq.d. And ran sudo service network-manager restart.

And then I got this in my syslog:

Oct 18 10:21:10 localhost dnsmasq[30777]: started, version 2.59 DNS disabled



Updates on my Lenovo X230 situation: Skype, screencap work; Vidyo not so much

Here was my wish list from before:

  • Camera working: Done! The trick was ‘uvcvideo‘, which I eventually built as a kernel module.
  • A Skitch replacement: Mostly done. I was given Shutter Project as a recommendation. I haven’t had a look at it yet. PrtSc actually takes pics of my visible desktop and I added a Firefox Addon called “Awesome Screenshot”. That solves my problems for now.
  • Vidyo working: Not working. I can now get video, and audio OUT, but I can’t hear other people. I need to dig into and troubleshoot this more. Skype, however, does work well. It does tend to flake out (slow video, loss of audio) far more on the Lenovo than on the Mac.
  • A package for my .bash_profile, .ssh and .gpg directories that I can install in any new system: Not done.
  • A better driver for the touchpad that doesn’t let my mouse jump around while I’m typing: Not done.
  • Change configuration to have the mouse behave like the latest OS X (reverse scrolling): Not done.

Overall, I feel much more comfortable on my Linux laptop now than my Mac. The mousing in particular is frustrating without buttons on the Mac.

I still switch back and forth because of Vidyo. I’m hoping in the next week or so to figure out what’s wrong with my audio and get it solved for good.

The nicest productivity improvements have been around test servers like HBase and Thrift, and being able to recompile my kernel at a moment’s notice for new features.

User Groups redux

lousy cup!
actually, i love this cup. thanks, eric! :)

It’s a bit late for an “announcement”, but Gabrielle and I are re-presenting the User Groups talk to the Portland Linux Users Group tonight. We’re all about audience participation, and so we’re going to focus on helping PLUG pick a few topics and presenters for upcoming meetings. And whatever else they want to talk about :)

Meeting starts at 7pm and here’s where:

Fariborz Maseeh College of Engineering & Computer Science Building
Room FAB 86-01 (This is in the basement.)
The building is on SW 4th across from SW College Street.
See location H-10 on map at http://pdxLinux.org/campus_map.jpg

Beer afterward at Jax!

Jax Bar And Restaurant
826 SW 2nd Avenue