Qemu networking issue

[Andrew Elmore]

In playing with qemu recently, I had a similar lack of connectivity until
I ran a "ifconfig bridge0 up" command.  One of those moments where I slap my forehead and say "Doh!".

AE

> -----Original Message-----
> From: owner-freebsd-emulation at freebsd.org [mailto:owner-freebsd-
> emulation at freebsd.org] On Behalf Of Trent Nelson
> Sent: Thursday, August 02, 2007 12:19 PM
> To: freebsd-emulation at freebsd.org
> Subject: Qemu networking issue
> 
> [ 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.
> 
> 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
> eventually fail.  If I picked an IP address like 192.168.0.1, it would
> go through, but there wouldn't actually be any network connectivity
> between the host/guest.
> 
> 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,
> also to be expected.  I tried a few things like using the qemu mac
> address for tap0, setting tap0's inet to 205.97.38.47 instead of
> 0.0.0.0, keeping 0.0.0.0 but having 205.97.38.47 as an alias, setting
> bridge0's inet to 205.97.38.47 and playing with the arp table to coerce
> things further, but nothing resulted in traffic between the host/guest.
> 
> Anyone have any insight?
> 
> 	Trent.
> 
>  [1]: http://www.nabble.com/Virtual-network-with-qemu-t3940434.html
>  [2]:
> http://docs.freebsd.org/cgi/getmsg.cgi?fetch=111250+0+archive/2007/freeb
> sd-emulation/20070603.freebsd-emulation
>  [3]: http://forums.bsdnexus.com/viewtopic.php?id=1563
>  [4]: http://acidos.bandwidth-junkies.net/index.php?Sect=qemu
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