[CentOS-virt] KVM: bridge configuration for static IP address

Christopher G. Stach II cgs at ldsys.net
Fri Dec 11 11:32:24 UTC 2009

----- "rewing" <rewing at howfortune.com> wrote:

> I need to allocate public IP address to two guest os.
> I have only 2 network card Interface on server. say eth0 and eth1.
> I set eth1 a public IP address. so it should in
> # vi /etc/sysconfig/ifcfg-eth1
> DEVICE=eth1
> BOOTPROTO=static
> HWADDR=00:1a:4d:83:ad:00
> ONBOOT=yes
> TYPE=Ethernet
> Question 1: do I have to add GATEWAY= to above setting?

GATEWAY probably belongs in /etc/sysconfig/network...

> Question 2: do I need to add the rest 2 IP addresses in br0?


> or I
> should keep br0 with no IP address and set IP in guest OS directly?

Yep. However, if you do that, you will need something acting as the gateway. If your host is going to be the gateway, it will need an address set in ifcfg-br0 and packet forwarding turned on. If eth1 and br0 are both in the same [public] network, you should just set the public IP address on br0 and add both eth0 and eth1 to the bridge and turn on STP.

(I don't see why you need eth0 in this mix at all if you are just using it for guests on the local machine.)

Christopher G. Stach II

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