From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: Mac-Address uniqueness Date: Thu, 31 May 2007 23:43:43 -0700 Message-ID: <465FC01F.4050105@zytor.com> References: <465E98B7.5050402@univie.ac.at> <465F72EA.9080608@zytor.com> <465FBC08.7000102@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Axel Kittenberger To: Avi Kivity Return-path: In-Reply-To: <465FBC08.7000102-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Avi Kivity wrote: > H. Peter Anvin wrote: >> Axel Kittenberger wrote: >> >>> Unfortunally all machines detect the same ethernet address >>> '52:54:00:12:34:56'. Which you can guess what i means, networking comes >>> and goes whatever machine last the ethernet address got hold of from the >>> gateway. I tried specifing an ethernet-adress with "-net >>> nic,macaddr=$MAC" but this also didn't work through. >>> >>> For now I just hardseted the mac in all machines to 52:54:00:12:34:57, >>> 52:54:00:12:34:58 and so on. >>> >>> >> This is a Qemuism. I always thought it was dumb, but I guess Qemu >> wanted reproducibility over everything. >> >> IMNSHO it would have been much better to default to a random value >> (meaning that all except the bottom 2 bits of the first octet are >> random, those bits should be set to 10 binary.) >> >> > > That tends to consume dhcp leases quickly, if you start guests often (as > I do). Also, some distributions use the mac address as a key for naming > interfaces; if it changes, the guest gets confused > The right solution to that, of course, is a VM definitions file, so the random Ethernet address is only generated once. For Qemu/KVM, that could at least in theory simply be a shell script. -hpa ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/