AFAIK every NIC manaufacturer is allocated a 2 (or is it 3?) byte prefix for the
device addresses. This prevents address clashes during ARP. Are there any
guidelines on what macs to assign to domU devices? Or is this even something
that one needs to consider?
--
mike kenny
Linux Registered User #381724
LPI ID# 80080
"Hell, there are no rules here, we''re just trying to accomplish
something"
Thomas Edison
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This should not be a problem - as long as all your DomU''s on the same machine have unique numbers between themselves, that''s sufficient. Since the mac-address gets translated/replaced when you send the packet out to the outside (if that happens at all) through the Dom0, you don''t need to worry about the mac-address of your DomU being seen by some other device outside your virtual set of machines. -- Mats> -----Original Message----- > From: xen-users-bounces@lists.xensource.com > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of > Mike A. Kenny > Sent: 26 April 2006 10:28 > To: xen-users > Subject: [Xen-users] mac addresses domUs > > AFAIK every NIC manaufacturer is allocated a 2 (or is it 3?) > byte prefix for the device addresses. This prevents address > clashes during ARP. Are there any guidelines on what macs to > assign to domU devices? Or is this even something that one > needs to consider? > > -- > mike kenny > Linux Registered User #381724 > LPI ID# 80080 > > "Hell, there are no rules here, we''re just trying to > accomplish something" > Thomas Edison > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Wednesday 26 April 2006 7:06 am, Petersson, Mats wrote:> This should not be a problem - as long as all your DomU''s on the same > machine have unique numbers between themselves, that''s sufficient. Since > the mac-address gets translated/replaced when you send the packet out to > the outside (if that happens at all) through the Dom0, you don''t need to > worry about the mac-address of your DomU being seen by some other device > outside your virtual set of machines.if using the bridged network setup, ''internal'' mac addresses will pass unchanged to the ''real'' network. on NAT and routing setups they would remain private to the physical box. -- Javier _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Mike A. Kenny wrote:> AFAIK every NIC manaufacturer is allocated a 2 (or is it 3?) byte prefix for the deviceaddresses. This prevents address clashes during ARP. Are there any guidelines on what macs to assign to domU devices? Or is this even something that one needs to consider?>Mike, the Users Manual (located at http://www.cl.cam.ac.uk/Research/SRG/netos/xen/readmes/user/user.html ) says the following: "You may also want to edit the vif variable in order to choose the MAC address of the virtual ethernet interface yourself. For example: vif = [''mac=00:16:3E:F6:BB:B3''] If you do not set this variable, xend will automatically generate a random MAC address from the range 00:16:3E:xx:xx:xx, assigned by IEEE to XenSource as an OUI (organizationally unique identifier). XenSource Inc. gives permission for anyone to use addresses randomly allocated from this range for use by their Xen domains." -- Anthony Valentine Asst. I.T. Manager Spenard Builders Supply UNIX was not designed to stop you from doing stupid things, because that would also stop you from doing clever things. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Anthony Valentine wrote:> "You may also want to edit the vif variable in order to choose the MAC > address of the virtual ethernet interface yourself. For example: > > vif = [''mac=00:16:3E:F6:BB:B3''] > > If you do not set this variable, xend will automatically generate a > random MAC address from the range 00:16:3E:xx:xx:xx, assigned by IEEE > to XenSource as an OUI (organizationally unique identifier). XenSource > Inc. gives permission for anyone to use addresses randomly allocated > from this range for use by their Xen domains." >This script will probably be useful #!/bin/bash prefix="00:16:3E" mac="$prefix" for seqnum in 1 2 3 ;do part=`dd if=/dev/random bs=1 count=1 2>/dev/null | xxd -ps -u` mac="$mac:$part" done echo $mac -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Anthony Valentine wrote:> "You may also want to edit the vif variable in order to choose the MAC > address of the virtual ethernet interface yourself. For example: > > vif = [''mac=00:16:3E:F6:BB:B3''] > > If you do not set this variable, xend will automatically generate a > random MAC address from the range 00:16:3E:xx:xx:xx, assigned by IEEE > to XenSource as an OUI (organizationally unique identifier). XenSource > Inc. gives permission for anyone to use addresses randomly allocated > from this range for use by their Xen domains." >This script will probably be useful #!/bin/bash prefix="00:16:3E" mac="$prefix" for seqnum in 1 2 3 ;do part=`dd if=/dev/random bs=1 count=1 2>/dev/null | xxd -ps -u` mac="$mac:$part" done echo $mac -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thursday 27 April 2006 04:53, Fajar A. Nugraha wrote:> Anthony Valentine wrote: > > "You may also want to edit the vif variable in order to choose the MAC > > address of the virtual ethernet interface yourself. For example: > > > > vif = [''mac=00:16:3E:F6:BB:B3''] > > > > If you do not set this variable, xend will automatically generate a > > random MAC address from the range 00:16:3E:xx:xx:xx, assigned by IEEE > > to XenSource as an OUI (organizationally unique identifier). XenSource > > Inc. gives permission for anyone to use addresses randomly allocated > > from this range for use by their Xen domains." > > This script will probably be useful > > #!/bin/bash > prefix="00:16:3E" > > mac="$prefix" > for seqnum in 1 2 3 ;do > part=`dd if=/dev/random bs=1 count=1 2>/dev/null | xxd -ps -u` > mac="$mac:$part" > done > echo $macotherwise echo "00:16:3E:`dd if=/dev/random bs=1 count=3 2>/dev/null | xxd -u -g 1 | cut -d\ -f2-4 --output-delimiter :`" :-) -- <?php echo '' Emiliano Gabrielli (aka AlberT) '',"\n", '' socio fondatore e membro del direttivo del GrUSP '',"\n", '' AlberT_at_SuperAlberT_it - www.SuperAlberT.it '',"\n", '' IRC: #php,#AES azzurra.com '',"\n",''ICQ: 158591185''; ?> _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Thu, Apr 27 ''06 at 09:47, Fajar A. Nugraha wrote:> Anthony Valentine wrote: > >"You may also want to edit the vif variable in order to choose the MAC > >address of the virtual ethernet interface yourself. For example:Just for your info, there is a range: "fe:fd" of mac addresses reserved for personal use. You could just use the IPv4 addres to get the remaning 4 numbers. If your IPs are inique the MAC addresses will be, too. -- /"\ Goetz Bock at blacknet dot de -- secure mobile Linux everNETting \ / (c) 2006 Creative Commons, Attribution-ShareAlike 2.0 de X [ 1. Use descriptive subjects - 2. Edit a reply for brevity - ] / \ [ 3. Reply to the list - 4. Read the archive *before* you post ] _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users