kvm, failed to start network default in virsh

xxx@yyy:~$ virsh net-start default
error: Failed to start network default
error: internal error '/sbin/iptables --table filter --delete INPUT --in-interface virbr0 --protocol udp --destination-port 69 --jump ACCEPT' exited with non-zero status 1 and signal 0: iptables: Bad rule (does a matching rule exist in that chain?).

in messages:
Dec 27 23:15:39 yyy libvirtd: 23:15:39.512: warning : networkAddIptablesRules:850 : Could not add rule to fixup DHCP response checksums on network 'default'.
Dec 27 23:15:39 yyy libvirtd: 23:15:39.512: warning : networkAddIptablesRules:851 : May need to update iptables package & kernel to support CHECKSUM rule.

and there is no virbr0 interface.



Solution:

xxx@yyy:~# /etc/init.d/dnsmasq stop

xxx@yyy:~$ virsh net-start default
Network default started

xxx@yyy:~$  ifconfig virbr0

virbr0    Link encap:Ethernet  HWaddr b2:f4:53:82:49:67  

          inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0

          inet6 addr: fe80::b0f4:53ff:fe82:4967/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:0 errors:0 dropped:0 overruns:0 frame:0

          TX packets:56 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0 

          RX bytes:0 (0.0 B)  TX bytes:8457 (8.4 KB)

That it!