Re: [Qemu-discuss] About how to connect from guest "10.0.2.15" to remote "192.168.1.xx"

[Mike Lovell]

it does match. i just now ran a test and i was able to ping 10.0.2.2 but 
not able to ping anything else. despite not being able to ping outside 
the 10.0.2.0/24 network, i was able to do the wget i listed before and 
connectivity to the rest of the world works. don't expect ping to be a 
good test when using user networking and talking to things outside of 
10.0.2.2.

mike

On 02/14/2012 05:30 PM, Qi Zhang wrote:
> Mike:
>         My guest can ping to host with the address 10.0.2.2 but just
> can't ping to host's LAN interface 192.168.1.10, does that match with
> your point?
> Thanks
> Zhang Qi
>
> On Wed, Feb 15, 2012 at 1:33 AM, Mike Lovell<address@hidden>  wrote:
> > On 02/14/2012 02:21 AM, Qi Zhang wrote:
> > > Hi There:
> > >
> > >          I'm trying to use QEMU to emulate a simple Linux Guest for
> > > some specific task
> > >          I have download/compile the Linux 3.2.5 kernel and busybox
> > > 1.19.4 and successfully make the guest system running after some
> > > simple setup.
> > >          Also the guest system can mount host NFS after I set the eth0
> > > IP to 10.0.2.15.  (mount -t nfs 10.0.2.2:/xxx/xxx /tmp)
> > >
> > >          Now the host system is also connect to a LAN (192.168.1.10),
> > > and there is application running on the guest system, who want to talk
> > > to another server on the LAN (192.168.1.8)
> > >          but guest (10.0.2.15) can't ping to the remote server
> > > (192.168.1.8),
> > >          I have manually add the default gateway as 10.0.2.2, that
> > > still not work.
> > >          Destination     Gateway         Genmask         Flags Metric
> > > Ref    Use Iface
> > >          0.0.0.0         10.0.2.2        0.0.0.0         UG    0      0
> > >         0 eth0
> > >          10.0.0.0        0.0.0.0         255.0.0.0       U     0      0
> > >         0 eth0
> > >
> > >          Can anybody help me to figure it out?
> > >          Wish the solution is not about use the tap/bridge solution,
> > >          I was lack of related network knowledge and the only thing I
> > > know is use QEMU "user net" is something similar as "NAT" option in
> > > virtual box,
> > >          though when use NAT the host can't ping to guest, but the
> > > guest can ping to everywhere and there is no bridge I think
> > >
> > >          BTW:
> > >          my host system is Ubuntu 11.10 and the command to start the QEMU
> > > is
> > >          "qemu-system-x86_64 -kernel arch/x86/boot/bzImage -boot d
> > > -append 'console=ttyS0, 115200' -nographic -net nic -net user"
> >
> > if i remember correctly, the user networking doesn't support ping or various
> > other ICMP messages. it uses a limited IP stack directly in the qemu process
> > and doesn't support everything that the kernel's IP stack supports. after
> > you set the ip address and default gateway in the guest, try connecting to
> > the service you want to talk to or try putting a web page through wget. i
> > frequently just use `wget http://google.com/` to test network connectivity
> > when using user networking.
> >
> > mike