Qemu networking issue

[Bakul Shah]

> [ Please CC me on replies as I'm not subscribed to this list. ]
> 
> I've got a 6.2-STABLE box that I'm running qemu 0.9.0 on, hosting a
> Windows 2003 guest OS.  I've got an em0 interface configured with the IP
> address 216.203.62.30 (default route: 216.203.62.29), as well as ten
> aliased (public) IPs, one of which happens to be 205.97.38.47, which I
> want to dedicate to this particular virtual machine, as if it were a
> jail.

Why are you using aliases?  If you use a bridge, each
connected host will present its own mac address and the
bridge itself is supposed to simply pass on a packet to the
appropriate interface.

> How do I get the Windows guest to use the 205.97.38.47 IP address?
> After a day of googling and trying half a dozen different approaches,
> nothing I try seems to work.
> 
> I've tried the sysctl net.link.ether.bridge and ifconfig bridge0
> approaches mentioned in [1-4].  This initially involved having a tap0
> inet 0.0.0.0 broadcast 0.255.255.255 interface, and a bridge0 with
> em0,tap0 (and no assigned IP for the bridge), but when I tried to tell
> the Windows box to use IP 205.97.38.47 (after I've removed this aliased
> IP from em0), subnet 0xffffff00, gateway 216.203.62.29, the local
> connection properties dialog would hang with 'Acquiring address...' then

This seems to say that your windows box expects a DHCP server
to be running somewhere.  What happens when you do manual IP config
on windows?

> When 205.97.38.47 was aliased to em0, Windows would complain that there
> was another IP on the network with the same IP (which is to be expected
> I guess), and dmesg would have a bunch of arp messages about the qemu
> guest mac address '52:54:00:12:34:56' trying to use em0's 205.97.38.47,

This happens because you are aliasing a bunch of IP addresses
to the same phys. interface.  You don't need aliases.
Instead either do static IP addressing in Windows or decide
on which MAC address you going to use for which virtual
machine and teach your DHCP server about that.

We need a `qemu-config' program to configure one of many
alternatives since everyone seems to go through the same
steps.