I want to run dnsmasq on my local machine in order to configure a wildcard to resolve to for testing purposes.

However, when I went to start dnsmasq with systemd I got the following error message:

[root@dhcppc4 ~]# systemctl status dnsmasq -l
● dnsmasq.service - DNS caching server.
   Loaded: loaded (/usr/lib/systemd/system/dnsmasq.service; disabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Fri 2015-10-09 21:49:58 BST; 14s ago
  Process: 2652 ExecStart=/usr/sbin/dnsmasq -k (code=exited, status=2)
 Main PID: 2652 (code=exited, status=2)

Oct 09 21:49:58 dhcppc4 systemd[1]: Started DNS caching server..
Oct 09 21:49:58 dhcppc4 systemd[1]: Starting DNS caching server....
Oct 09 21:49:58 dhcppc4 dnsmasq[2652]: dnsmasq: failed to create listening socket for port 53: Address already in use
Oct 09 21:49:58 dhcppc4 systemd[1]: dnsmasq.service: main process exited, code=exited, status=2/INVALIDARGUMENT
Oct 09 21:49:58 dhcppc4 systemd[1]: Unit dnsmasq.service entered failed state.
Oct 09 21:49:58 dhcppc4 systemd[1]: dnsmasq.service failed.

Confused as to how port 53 is taken with no current DNS server running (and confirmed with dig @, I ran netstat -ln and found a process listening on port 53 on address

tcp        0      0*               LISTEN
udp        0      0* 

An ifconfig shows that is the virtual interface virbr0.

A quick Google search and wiki later, I understand that libvirt provides virtual networking to the host in order to abstract physical interfaces. Libvirt uses a virtual network switch through which all traffic is routed [1]. The default virtual network switch, virbr0, is created when the daemon first starts.

I can then confirm that I can send queries via DIG to dnsmasq on this interface:

[grobinson@dhcppc4 ~]$ dig @ +short

Question 1: I don't understand the reason behind having dnsmasq listen on this virtual interface? For /etc/resolv.conf I can see that the DNS servers configured at the DHCP server tell the machine to direct queries to Google DNS servers. What is its use?

# Generated by NetworkManager

I find that I can edit /etc/NetworkManager/NetworkManager.conf and add the line dns=dnsmasq and then restart network manager with systemd. From here on network manager is configured to direct queries to dnsmasq on the loopback address and can be seen with a simple call to dig:

[grobinson@dhcppc4 ~]$ dig @ +short

The netstat -ln output now shows two sockets bound and listening on port 53:

tcp        0      0  *               LISTEN     
tcp        0      0*               LISTEN 

Question 2: how come network manager can start dnsmasq on and I can't with systemctl? Is that because the default configuration is attempting to listen on all interfaces, which fails for virbr0? I just need to state the desired interface?

Question 3: It looks like there are two configuration options for dnsmasq: /etc/dnsmasq.conf and a folder /etc/NetworkManager/dnsmasq.d/ where configuration files can be written. It looks like the latter is for when dns=dnsmasq is set and dnsmasq listening on since editing /etc/dnsmasq.conf has no effect on queries to @ Could the former be for dnsmasq in libvirt?


3 Answers 3


By default, libvirt starts a dnsmasq instance for each of its' virtual interface bridges. This is done to provide DHCP service to VM's running in a virtual network.


Essentially, the virbr bridge is created by libvirt every time you spin up a VM using the default settings. If you want to prevent this from happenning, you need to create the bridge yourself before starting up a VM and then start it up in "bridge" mode, speciying your custom bridge as the argument. Here is a man page that explains it pretty well. Look under the --network option:


Every time you create a "virtual network" in libvirt, it also starts an instance of dnsmasq for it. So, again, you have to stop using libvrt's virtual networks and go manual.

  • 1
    I don't get it. That whole dnsmasq automation for bridges in libvirt ruins virsh net-* shell functions to complete uselessness as there can be scenarios in which you don't want to use dnsmasq. Not even an arg or switch to disable that behavior.
    – 3ronco
    Oct 10, 2018 at 12:02
  • Read my original reply - the answer is there. In short - there is a simple way to avoid spinning up an instance of dnsmasq.
    – user65677
    Oct 11, 2018 at 22:34
  • How could i overlook this? Found it elsewhere: libvirt.org/git/…
    – 3ronco
    Oct 12, 2018 at 11:20

If you want your local /etc/hosts changes to propagate to your VMs using the same interface you can simply SIGHUP the local libvirt process.


Configure your dnsmasq instance to explicit list of interfaces you want it to listen on.

In /etc/dnsmasq.conf you can use either interface names interface=eth0 or interface IP listen-address= Even with this set, dnsmasq will helpfully bind to all interfaces, so disable that by adding bind-interfaces to the config file.

Alternatively, in the config file, specify interface blacklist with except-interface=virtbr*.


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