From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.33) id 1BdBMf-0000Cg-Tf for qemu-devel@nongnu.org; Wed, 23 Jun 2004 13:16:50 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.33) id 1BdBMf-0000CN-5H for qemu-devel@nongnu.org; Wed, 23 Jun 2004 13:16:49 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.33) id 1BdBMf-0000CD-0S for qemu-devel@nongnu.org; Wed, 23 Jun 2004 13:16:49 -0400 Received: from [128.117.21.121] (helo=phaedrus.cgd.ucar.edu) by monty-python.gnu.org with esmtp (Exim 4.34) id 1BdBLD-0005TR-Rl for qemu-devel@nongnu.org; Wed, 23 Jun 2004 13:15:20 -0400 Date: Wed, 23 Jun 2004 11:15:09 -0600 From: Phil Rasch Subject: Re: [Qemu-devel] Question about tun/tap networking Message-ID: <20040623171509.GC6368@ucar.edu> References: <200406230754.07821.pjr@ucar.edu> <20040623170325.GB22835@jbrown.mylinuxbox.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040623170325.GB22835@jbrown.mylinuxbox.org> Reply-To: pjr@ucar.edu, qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: jbrown106@swift-mail.com Cc: qemu-devel@nongnu.org Thanks Jim, I dont really require everything to be on the same subnet. I just hate having to figure out how to setup the nameservers, gateways, IP numbers etc on each virtual machine I create. It would have been great to just tell the virtual machine to "go get the relevant info from the DHCP server". Maybe the alternative isnt really a big deal, but like I said, I am a beginner at configuring networks. Phil On Wed, Jun 23, 2004 at 01:03:25PM -0400, Jim C. Brown wrote: > On Wed, Jun 23, 2004 at 07:54:07AM -0600, Phil Rasch wrote: > > I have been running a mixture of linux and windows machines, all real machines > > on a LAN connected to the outside world through a router, which is acting as > > my DHCP server, DNS server, and gateway machine. > > > > The LAN subnet is 192.168.0.* > > > > Now I want to connect up the virtual machine running under QEMU. I want the > > virtual machine to be on the same subnet as the real machines, and to use > > DHCP from the router to get all the relevant info. > > That is tricky. You will need to look into bridging. > > > > > Jim suggested the following commands for somebody else on the mailing list, > > but I think that was headed towards devising a subnet that two virtual > > machines could use to talk to each other. > > > > [/space/qemu/qemu-0.5.4/ $] su root > > [/space/qemu/qemu-0.5.4/ #] vde_switch -daemon -tap tap0 > > [/space/qemu/qemu-0.5.4/ #] ifconfig tap0 192.168.1.254 > > [/space/qemu/qemu-0.5.4/ #] chmod 777 /tmp/vde.ctl > > [/space/qemu/qemu-0.5.4/ #] exit > > [/space/qemu/qemu-0.5.4/ $] vdeq qemu -hda disk1.img > > That is correct. You now have 2 subnets, 198.168.0.* for the real network > and 192.168.1.* for qemu/VDE. > > > > > The thing I dont understand is whether the above command is setting up > > seperate subnet for the virtual machines, or whether I can also set them up > > on the same subnet as the real machines, and let them see the DHCP server, > > etc, and if so, then how to do it. So far, I have never needed to learn the > > subtleties of ifconfig. Am I going to have to do so now? Do you have anymore > > advice on using VDE and QEMU together for my purpose? > > Like I said, you will need to use bridging. After you have loaded vde_switch, > skip the ifconfig step, and combine eth0 and tap0 into br0. Then you will need > to set up br0 properly. If you are going to use bridging however, I recommend > you use tuntap instead of VDE. (You don't really need VDE if you are going to > to use bridging.) If you decide to go with tuntap and bridging, you should look > in the qemu archives for assistance. There are several messages that appear > to have useful information on this topic, such as this one which tells you > step-by-step: > > http://lists.gnu.org/archive/html/qemu-devel/2004-05/msg00032.html > > (you'll need to do a 'brctl addif br0 eth0' and a 'ifconfig br0 192.168.0.XXX' > for the machine that will be running qemu (almost certainly in one of the startup > scripts, as eth0 must not have an ip yet) but otherwise the instructions are > exactly the same.) > > I am curious though, why do you require that the virtual machines be on the same > subnet as the real ones? > > > > > Thanks > > > > Phil > > -- > Infinite complexity begets infinite beauty. > Infinite precision begets infinite perfection. -- Phil Rasch, Climate Modeling Section, National Center for Atmospheric Research Mail --> P.O. Box 3000, Boulder CO 80307 Shipping --> 1850 Table Mesa Dr, Boulder, CO 80305 email: pjr@ucar.edu, Web: http://www.cgd.ucar.edu/cms/pjr Phone: 303-497-1368, FAX: 303-497-1324