On Mon, Jun 4, 2012 at 10:44 PM, Gordon Messmer <yinyang at eburg.com> wrote: > >> On a separate note however, I'd still like to know how to use a bridge to >> route packets between two networks.....say network card having >> address...192.168.1.3 and a kvm based virtual network say >> 172.31.1.0/24needing to use this device for Internet access (through >> router 192.168.1.1) >> using a bridge? How to do it? > > If your networks are on different IPv4 broadcast domains (as you > describe), you don't want a bridge. > > If you want bridged networking with KVM, your guests will be on the same > network as the host. They'll use your existing DHCP services and > routing. They can be configured according to this document: > http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6-Beta/html/Virtualization_Host_Configuration_and_Guest_Installation_Guide/sect-Virtualization_Host_Configuration_and_Guest_Installation_Guide-Network_Configuration-Network_Configuration-Bridged_networking_with_libvirt.html > > That configuration used to be reflected here: > http://wiki.centos.org/HowTos/KVM > ...but someone went and put in some really braindamaged instructions. > That should be fixed or removed. > In case of a separate network, should it not be possible to create a dummy bridge or something and forward packets through maybe...NAT....A guy talks of this kind of thing here http://ghantoos.org/2007/10/24/kvmqemu-bridging-with-dummy-network-card/ but I don't quite understand it, because I am not familiar with /etc/network/interfaces.....seems to be ubuntu or some other linux. I am using /etc/sys-config/network-scripts/ifcfg-xxx files. or any other forwarding system...but don't know how? Any ideas of how to do it with separate IP addressing? The main network is out of my control and I cannot use its IP addresses. Rgds. Sanjay.