Hi

I am new to KVM virtualization
I am running KVM under Centos 6.3 and I would like to ask one question.

When I start libvirt service it automaticly generates iptables rules for virbr0 network but I don't know where is config for this rules.

/etc/sysconfig/iptables doesn't have this rules

[root@dubnik dubnik]# iptables -nvL -t nat
Chain PREROUTING (policy ACCEPT 2 packets, 92 bytes)
pkts bytes target prot opt in out source destination

Chain POSTROUTING (policy ACCEPT 1 packets, 71 bytes)
pkts bytes target prot opt in out source destination
0 0 MASQUERADE tcp -- * * 192.168.123.0/24 !192.168.123.0/24 masq ports: 1024-65535
0 0 MASQUERADE udp -- * * 192.168.123.0/24 !192.168.123.0/24 masq ports: 1024-65535
0 0 MASQUERADE all -- * * 192.168.123.0/24 !192.168.123.0/24

Chain OUTPUT (policy ACCEPT 1 packets, 71 bytes)
pkts bytes target prot opt in out source destination

[root@dubnik dubnik]# cat /etc/sysconfig/iptables
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

so where can I find config for this nat rules ?

Thanks