[libvirt-users] libvirt and NAT on a system that already has a DHCP server

[Daniel P. Berrangé]

On Thu, Feb 01, 2018 at 09:19:11AM -0500, Laine Stump wrote:
> On 01/30/2018 07:37 PM, john at bluemarble.net wrote:
> > I'm trying to use virt-manager and qemu/kvm on Arch Linux. The box I'm
> > using is also the router for my house. It runs a kea DHCP server. When I
> > try to start the default NAT network, it can't start dnsmasq because that
> > port is already bound. Is there a way to have it not bind on this
> > interface? I see there is an except-on statement in the dnsmasq.conf, but
> > I can't add lines to that directly, and I didn't see any way to add
> > special options using virsh net-edit default.
> 
> The dnsmasq processes run by libvirt to serve dhcp for the virtual
> networks already does this - they listen *only* on the bridge created
> for their particular network, nothing else. Your problem is that your
> host system's dhcp server has been configured to automatically listen on
> all interfaces.
> 
> So it's not the configuration of the libvirt network that needs to
> change, it's the configuration of the host system's dhcp server. It
> needs to be told that it shouldn't automatically listen on all new
> interfaces, but to just listen on certain specific interfaces.

Checkout this

https://wiki.libvirt.org/page/Libvirtd_and_dnsmasq

Regards,
Daniel
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