How to remove virbr0

I play around with Linux virtualization software in my network.
A few day after i deploy Virt Server, something going wrong with my network.
Several client got IP from unidentified  DHCP server....

After taking a few step 'old school network troubleshooting'
I finally found that my Virt server act as dhcp server.
The ip's is broadcast from this interface: virbr0
here's step to disable this interface

# virsh net-list

to view virtual network interface

then, disable it straight away.. heheh..
 
# virsh net-destroy default
# virsh net-undefine default
# service libvirtd restart
# ifconfig 

Done...