Bridged Network with libvirt on centos

Question

I'm trying to configure Bridged Network by creating a network script at /etc/sysconfig/network-scripts/ifcfg-br0:

DEVICE="br0"
NM_CONTROLLED="no"
ONBOOT="yes"
TYPE="Bridge"
BOOTPROTO="static"
IPADDR="10.110.10.15"
GATEWAY="10.110.10.1"
DNS1="8.8.8.8"
DNS2="8.8.4.4"
MTU="1500"
NETMASK="255.255.255.0"
DEFROUTE="yes"
IPV4_FAILURE_FATAL="yes"
IPV6INIT="no"
NAME="System br0"

Where can I find appropriate IPADDR, GATEWAY, NETMASK ?

And for /etc/sysconfig/network-scripts/ifcfg-eth0:

DEVICE="eth0"
BOOTPROTO="none"
HOSTNAME="localhost.localdomain"
HWADDR="00:9C:02:97:86:70"
IPV6INIT="no"
MTU="1500"
NM_CONTROLLED="no"
ONBOOT="yes"
TYPE="Ethernet"
NAME="System eth0"
BRIDGE="br0"

Where can I find HWADDR ?

Answer 1

The IPADDR / GATEWAY / NETMASK are determined by your network provider. Use the same values you already had used for eth0 before setting up bridging. The bridge does not have to use static address assignment - it is valid to have BOOTPROTO=dhcp and let it be dynamically assigned if that's what your eth0 config originally used.

HWADDR is just another name for MAC address - you can see it from 'ifconfig' or 'ip' command output.

Answer 2

Where can I find appropriate IPADDR, GATEWAY, NETMASK ?

Your network provider typically assigns them to you...

Where can I find HWADDR ?

The HardWare ADDress, also know as the MAC-address is a unique identifier assigned to network interfaces at the hardware level (although in some drivers you can override it in software and in for instance virtual servers it is obviously also a configurable property set on the hypervisor).
You can display it with ip addr show, cat /sys/class/net/*/address or ifconfig -a.