[CentOS] Connecting ethX devices directly to a KVM/QEMU guest OS (no bridging)

Chuck Munro chuckm at seafoam.net
Wed Jan 18 19:45:45 UTC 2012

Hello CentOS gurus, and a belated Happy New Year (or an early Happy 
Chinese New Year).

I'm in the process of building a CentOS-6 KVM host machine whose only 
function will be to run four independent 'm0n0wall' firewall guest 
instances. I have a couple of quad-port Intel NICs to provide four 
WAN-side and four LAN-side ports, which will not be shared with any 
other guests. Remote access to the host CentOS is via a separate 
on-board NIC, so the Intel ports are free to assign.

I've Googled until I'm blue in the face, but haven't found a clear 
explanation of how I can assign each ethX device directly to the guest 
OS rather than going thru the usual bridge configuration. I need to 
allow the m0n0wall OS to assign the LAN and WAN IP addresses, if that's 
possible without using a bridge.

Using the Virtual Machine Manager GUI to create the VM guests (which 
boot up and run nicely), the drop-down list shows all of the ethX 
devices greyed out. Do I need to somehow start the NICs without 
assigning IP addresses, so that they show up in 'ifconfig'?

Can anyone provide a clear, easy-to-understand procedure for doing this? 
If necessary, I don't mind using the command-line to create the VMs but 
the docs aren’t totally clear (to me, at least) regarding NIC assignment.

Thanking you in advance for your suggestions,

More information about the CentOS mailing list