I upgraded from CentOS 5.9 to CentOS 6.4.

I try to reuse my virtual machines and am only partially successful: I

can run them, I just cannot get the network OK and need some help with that.

What I had in the past was pretty simple: both the host and the VM?s

used eth0 and each had an IP in the same subnet and could communicate freely.

With the new install it seems somewhat more complex and I think I need to configure a bridge and use that.

Unfortunately, info I find through google is overwhelming and

confusing. All examples either configure something else, or the outcome is not what? expected.

So: how to go about setting things up to have say:

My physical machine is on 192.168.0.90

My Virtual machines are on 192.168.0.100 and 101.

These are to be fixed addresses.

The 2 VM?s have to communicate with each other and with the physical machine.

The VM?s do not necessarily need to communicate with the rest of the world.

The physical machine needs to communicate with the rest of the world.

I use:

• CentOS-6.4_64

• Virtual Machine Manager 0.9.0

• xen 4.2.3

• libvirt 0.10.2.7-5

• VM?s show Hypervisor = xen (fullvirt)

• Emulator = qemu-dm

• NIC points to Shared device name virbr0

• on the host, virbr0 has IQ 192.168.122.1

I have been fighting this for 2 weeks, now. I tried to follow several

advises which resulted in either the VM?s not connecting to anything,

or my host losing its connection to the rest of the world, or both. So either I still do something not-right, or I follow the wrong gidelines.

Can someone give me a push in the right direction, please?

Thanks to all who responded to this: it is working now. Solution was relatively easy and mainly a matter of understanding the "ifcfg-eth0 - like" files.

What I did: 1 - yum install bridge-utils 2 - change /etc/sysconfig/network-scripts/ifcfg-eth0 to: DEVICE="eth0" BOOTPROTO=none ONBOOT="yes" TYPE="Ethernet" HWADDR=xx:xx:xx:xx:xx:xx BRIDGE="br0" USERCTL=no IPV6INIT=no NM_CONTROLLED="no" 3 - change change /etc/sysconfig/network-scripts/ifcfg-br0 to: DEVICE="br0" BOOTPROTO=none ONBOOT="yes" IPADDR=192.168.0.95 NETMASK=255.255.255.0 GATEWAY=192.168.0.1 DNS1="192.168.0.1" PEERDNS="yes" TYPE="Bridge" DELAY=0 STP=off USERCTL=no IPV6INIT=no NM_CONTROLLED=no 4 - /etc/init.d/network restart 5 - choose Host device eth0 (Bridge 'br0') in the VM-manager GUI for the virtual-machine's NIC 6 - restart the virtual machines

That made it all work. So what I had wrong initially were settings in the ifcfg-xxx files. There are different settings that may work and I just tried some of the not-working combinations. Cheers, Koos.