Right. Sorry if this is a dumb question, but I'm rather confused over the configuration and operation of an ethernet bridge in linux.

Specifically, using CentOS 6.2 and want to have VM's on the main network, not within the default local NAT one.

Took me a bit to realize that NetworkManager was clobbering my customised ifcfg-* scripts , and that I had to disable it prior to trying to get a bridge working. (I learned later that, indeed, NetworkManager does not support ethernet bridges. Aha!)

I configured the test host with a static IP address on the local network, manually set the DNS servers, gateway, etc. Worked a treat. No issues pinging other machines on the local network nor others on the Internet.

I'll save everyone the confusion of all the steps I initially took--which worked, for the most part--and refer you to this lovely documentation on the subject: http://docs.redhat.com/docs/en-US/Re...g_with_libvirt (wish I had found it earlier! )

Just to verify I had things proper, I reinstalled the test box and followed the instructions for creating an ethernet bridge in the above link from Redhat. It was a pleasant surprise it worked the same way--so I must not have been completely wrong--but I remain confused on how it should work: if eth0 is the physical ethernet adapter, and br0 is defined as a bridge of eth0, why is it that, once I have added "Bridge=br0" to my ifcfg-eth0 file and created a similar ifcfg-br0 file as shown in the Redhat docs that I no longer have *any* IP address for my eth0? Not only does eth0 no longer have an IP address but br0 now has a dhcp-assigned address.

I can only ssh into the test box now by addressing its br0 address; what happened to eth0? Shouldn't eth0 remain and br0 "tag" along for the ride?

This probably is very likely simply a misunderstanding on my part of how a bridge device works in linux, but I was just hoping some kind networking guru far wiser than I might chip in as to why I'm seeing this configuration on the box after the addition and activation of the bridge.

Or is this simply working as designed, and I only need to reconfigure the ifcfg-br0 file to set it to the desired static IP I once had on eth0?

Thanks in advance for any insight on this!!

Are you talking about a bridge as in

1. a piece of hardware that connects to a wifi connection and turns that connection into a signal that can be plugged into an ethernet cable port of a computer or
2. a software adapter in the configuration of a virtual machine to allow a VM to connect directly to the local network?

Your question really is not presented clearly.

Try telling us what you are trying to do, what hardware and/or software components you are using, and what you have done in an organized sequential manner.