Linux Ethernet Bridging - Apr 2007 - [Bridge] bridge physical to several dummy interface

On 11/20/06, d tbsky <tbskyd@gmail.com> wrote:
> hi:
>    my purpose is to get several ip address  from dhcp server via single
> ethernet card, like xen or vmware can do.
>
> Regards,
> sky_li
>
I never worked with this, but I think you should try "User Mode Linux"
tools.
http://user-mode-linux.sourceforge.net/UserModeLinux-HOWTO.html

On Mon, 20 Nov 2006 11:55:12 +0800
"d tbsky" <tbskyd@gmail.com> wrote:
> hi:
> >    my purpose is to get several ip address  from dhcp server via
single
> > ethernet card, like xen or vmware can do.
> >
> > Regards,
> > sky_li
> >
That isn't going to work for a number of reasons. Probably the biggest is
that Linux doesn't bind IP addresses to interfaces, so the ARP etc is going
to be messed up.  You need to have separated IP stacks, like Xen, UML, etc
to make this work.

Hi:
    i want to bridge my eth0 interface to several dummy interface, like
vmware or xen did,
so i can request several dhcp ip address via several mac addresses.
   but i am stuck in the first step:
   assume my eth0 is 192.168.10.1, and it can ping 192.168.10.254.
    ifconfig br0 up
    brctl setfd br0 0
    brctl addif br0 eth0

    now i can not ping 192.168.10.254 anymore.
    but if i set 192.168.10.2 to br0, i can ping 192.168.10.254.
    and "dhclient eth0" can get ip addess from dhcp server(that
surprise
me!!)
    i try to add dummy interface to br0, but dummy interface can not work,
like eth0.
    "brctl showmac br0" give me may mac addresses, so i think bridging
is
working.

    i think i must misunderstanding the brindge concept.
    can i keep eth0 work after it join br0?
    thanks a lot for your help!!

Regards,
tbsky
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hi:
>    my purpose is to get several ip address  from dhcp server via single
> ethernet card, like xen or vmware can do.
>
> Regards,
> sky_li
>
>
>
> 2006/11/20, Abel Mart=EDn < abel.martin.ruiz@gmail.com>:
> >
> > On 11/18/06, d tbsky < tbskyd@gmail.com> wrote:
> > > Hi:
> > >     thanks for your reply. you say the bridge interface should
take
> > the ip
> > > address,
> > > not the nic. that's important. i think i go to the wrong
direction. i
> > want
> > > nic
> > > (eth0,dummy0) to have ip address, not br0. it seems not what
linux
> > bridge
> > > designed to do...
> > The problem is that a bridge device works at the link layer. A bridge
> > device doesn't know nothing about what is above link layer.
> > > by the way, i found if i set mac address manually :(eg: arp -s
> > > 192.168.10.254 x:x:x:x:x:x),
> > > then i can ping 192.168.10.254 via eth0. but i can never make
dummy0
> > work in
> > > any way.
> > >
> > > Regards,
> > > tbsky
> > Could you explain what your actual purpose is? I might be
> > misunderstanding you.
> >
>
>
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On 11/17/06, d tbsky <tbskyd@gmail.com> wrote:
> Hi:
>     i want to bridge my eth0 interface to several dummy interface, like
> vmware or xen did,
> so i can request several dhcp ip address via several mac addresses.
>    but i am stuck in the first step:
>    assume my eth0 is 192.168.10.1, and it can ping 192.168.10.254.
>     ifconfig br0 up
>     brctl setfd br0 0
>     brctl addif br0 eth0
>
>     now i can not ping 192.168.10.254 anymore.
You might be having a routing problem. Check your routing table with ip
route.
>     but if i set 192.168.10.2 to br0, i can ping 192.168.10.254.
>     and "dhclient eth0" can get ip addess from dhcp server(that
surprise
> me!!)
Try dhclient br0.
>     i try to add dummy interface to br0, but dummy interface can not work,
> like eth0.
>     "brctl showmac br0" give me may mac addresses, so i think
bridging is
> working.
>
>     i think i must misunderstanding the brindge concept.
When a nic is part of a bridge it's not supposed to have an address,
is the bridge interface which has to.
>     can i keep eth0 work after it join br0?
I think it does work, since it's the physical
>     thanks a lot for your help!!
>
One more thing: as you add interfaces to a bridge, the bridge MAC will
change to the lowest MAC of the attached interfaces.

Regards.