[Qemu-devel] Networking on Win2K host

[Qemu-devel] Networking on Win2K host

[Mike Tremoulet]

All --

Hopefully you can help me with this - I'm so close to having it
working, I can taste it.

I'm using Kazu's outstanding windows port
(http://www.h7.dion.ne.jp/~qemu-win/), although I have compiled my own
with Mingw/Msys, both with and without his networking patch.

Qemu itself seems to run quite well and quite fast.  The only hurdle I
have left is networking.  I have three interfaces on my Win2K host -
an integrated Ethernet NIC, a wireless NIC, and OpenVPN 2.0beta2
TAP-Win32 (installed in the process of trying everything).  When I
boot in Qemu, I get an IP address of 10.*.*.* assigned.  This
corresponds to nothing on my network.  I can resolve domain names, but
I cannot apparently send or receive traffic. If I execute "ping
google.com", the ping command comes back with an IP address for
google.com but no packets received.

For the "test" linux image available from the qemu site, I do not even
have an eth0 defined - there is no corresponding device, according to
the guest.

My questions are:
- What else must I do to configure the host side of networking?
- How do I know or define which adapter on my host is being used by qemu?

Host machine:
Win2K SP4, Winpcap 3.1beta3, TAP-Win32
Guests:
Gentoo 2004.2 livecd, Debian sarge livecd, Test linux image

There's a HOWTO waiting to be written on this...

Thanks in advance,
-- Mike

Re: [Qemu-devel] Networking on Win2K host

[Renzo Davoli]

On Mon, Aug 09, 2004 at 09:54:09AM -0500, Mike Tremoulet wrote:
> Qemu itself seems to run quite well and quite fast.  The only hurdle I
> have left is networking.  I have three interfaces on my Win2K host -
> an integrated Ethernet NIC, a wireless NIC, and OpenVPN 2.0beta2
> TAP-Win32 (installed in the process of trying everything).  When I
> boot in Qemu, I get an IP address of 10.*.*.* assigned.  This
> corresponds to nothing on my network.  I can resolve domain names, but
> I cannot apparently send or receive traffic. If I execute "ping
> google.com", the ping command comes back with an IP address for
> google.com but no packets received.
> 
The IP address 10.0.2.15 is the default address for the slirp (user-net)
support integrated inside qemu.
slirp does not need any configuration nor external tools.
It does *not* forward ping (ICMP) packets but it works with TCP
connections as it were a NAT (masquerading) router.

So if the guest os gets the address, it is able to resolve names, it is able
to ping 10.0.2.2 (the default route) everything should be okay.
If it resolves google.com but you cannot ping it... it is the standard
behavior.

Cross your fingers and Start your browser.

renzo

P.s. I have my experience on qemu for linux, but for user-net netowrking 
should behave in the same way.

Re: [Qemu-devel] Networking on Win2K host

[Mike Tremoulet]

Renzo --

Thanks for the tip - I'm going to throw things if I spent the weekend
sorting this out only because it doesn't forward pings... ;)

Unfortunately, resolution doesn't appear to be working now that I'm on
my work network and not at home.  Again, I don't know how to tell
which of three interfaces is used by slirp as the outbound side to the
world.

Still working on it,
-- Mike

On Mon, 9 Aug 2004 17:38:33 +0200, Renzo Davoli <renzo@cs.unibo.it> wrote:
> On Mon, Aug 09, 2004 at 09:54:09AM -0500, Mike Tremoulet wrote:
> > Qemu itself seems to run quite well and quite fast.  The only hurdle I
> > have left is networking.  I have three interfaces on my Win2K host -
> > an integrated Ethernet NIC, a wireless NIC, and OpenVPN 2.0beta2
> > TAP-Win32 (installed in the process of trying everything).  When I
> > boot in Qemu, I get an IP address of 10.*.*.* assigned.  This
> > corresponds to nothing on my network.  I can resolve domain names, but
> > I cannot apparently send or receive traffic. If I execute "ping
> > google.com", the ping command comes back with an IP address for
> > google.com but no packets received.
> > 
> The IP address 10.0.2.15 is the default address for the slirp (user-net)
> support integrated inside qemu.
> slirp does not need any configuration nor external tools.
> It does *not* forward ping (ICMP) packets but it works with TCP
> connections as it were a NAT (masquerading) router.
> 
> So if the guest os gets the address, it is able to resolve names, it is able
> to ping 10.0.2.2 (the default route) everything should be okay.
> If it resolves google.com but you cannot ping it... it is the standard
> behavior.
> 
> Cross your fingers and Start your browser.
> 
> renzo
> 
> P.s. I have my experience on qemu for linux, but for user-net netowrking
> should behave in the same way.
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>

Re: [Qemu-devel] Networking on Win2K host

[Renzo Davoli]

On Mon, Aug 09, 2004 at 12:20:29PM -0500, Mike Tremoulet wrote:
> Unfortunately, resolution doesn't appear to be working now that I'm on
> my work network and not at home.  Again, I don't know how to tell
> which of three interfaces is used by slirp as the outbound side to the
> world.

Mike,

the slirp tecnique works at user level, thus qemu+slirp acts as it were
a standard application.
All the TCP connections initiated from inside the guest os appear as
TCP connections created by the application qemu itself.

Thus the interface used by slirp is the same used by your browser and
by all the other applications on the host os.

(bind uses IP_ADDR_ANY)

ciao
	renzo

RESOLVED: Re: [Qemu-devel] Networking on Win2K host

[Mike Tremoulet]

It's working now.

What I learned from this is that, as you said, slirp essentially set
up a NAT behind 10.0.2.2.  However, this was not resolving until I
changed the /etc/resolv.conf on the Gentoo guest to point at
192.168.0.1.  (It was originally set for 10.0.2.3)

I think that, unless slirp is doing something I don't know about, that
qemu is using the TAP-Win32 adapter on my host machine, which is set
through Windows internet connection sharing (ICS) to go through my
ethernet adapter.  I'm not seeing traffic on the TAP adapter, though,
but nothing else I know of has an IP of 192.168.0.1.

Setting the resolv.conf got me network name resolution, and a test of
wget showed connectivity to the outside world.

I will be writing this up - that was too much effort not to share. 
What is the best place for that writeup?  And are there any more
details or answers to the original questions about qemu's interaction
with a windows host?

Thanks,
-- Mike

On Mon, 9 Aug 2004 12:20:29 -0500, Mike Tremoulet <coffeemike@gmail.com> wrote:
> Renzo --
> 
> Thanks for the tip - I'm going to throw things if I spent the weekend
> sorting this out only because it doesn't forward pings... ;)
> 
> Unfortunately, resolution doesn't appear to be working now that I'm on
> my work network and not at home.  Again, I don't know how to tell
> which of three interfaces is used by slirp as the outbound side to the
> world.
> 
> Still working on it,
> -- Mike
> 
> 
> 
> On Mon, 9 Aug 2004 17:38:33 +0200, Renzo Davoli <renzo@cs.unibo.it> wrote:
> > On Mon, Aug 09, 2004 at 09:54:09AM -0500, Mike Tremoulet wrote:
> > > Qemu itself seems to run quite well and quite fast.  The only hurdle I
> > > have left is networking.  I have three interfaces on my Win2K host -
> > > an integrated Ethernet NIC, a wireless NIC, and OpenVPN 2.0beta2
> > > TAP-Win32 (installed in the process of trying everything).  When I
> > > boot in Qemu, I get an IP address of 10.*.*.* assigned.  This
> > > corresponds to nothing on my network.  I can resolve domain names, but
> > > I cannot apparently send or receive traffic. If I execute "ping
> > > google.com", the ping command comes back with an IP address for
> > > google.com but no packets received.
> > >
> > The IP address 10.0.2.15 is the default address for the slirp (user-net)
> > support integrated inside qemu.
> > slirp does not need any configuration nor external tools.
> > It does *not* forward ping (ICMP) packets but it works with TCP
> > connections as it were a NAT (masquerading) router.
> >
> > So if the guest os gets the address, it is able to resolve names, it is able
> > to ping 10.0.2.2 (the default route) everything should be okay.
> > If it resolves google.com but you cannot ping it... it is the standard
> > behavior.
> >
> > Cross your fingers and Start your browser.
> >
> > renzo
> >
> > P.s. I have my experience on qemu for linux, but for user-net netowrking
> > should behave in the same way.
> >
> > _______________________________________________
> > Qemu-devel mailing list
> > Qemu-devel@nongnu.org
> > http://lists.nongnu.org/mailman/listinfo/qemu-devel
> >
>

Re: RESOLVED: Re: [Qemu-devel] Networking on Win2K host

[Renzo Davoli]

On Mon, Aug 09, 2004 at 12:48:28PM -0500, Mike Tremoulet wrote:
> What I learned from this is that, as you said, slirp essentially set
> up a NAT behind 10.0.2.2.  However, this was not resolving until I
true.
> changed the /etc/resolv.conf on the Gentoo guest to point at
> 192.168.0.1.  (It was originally set for 10.0.2.3)
> 
Strange, the slirp support has been designed to forward DNS on the
address 10.0.2.3 and the internal DHCP has been designed to broadcast this info.

> I think that, unless slirp is doing something I don't know about, that
> qemu is using the TAP-Win32 adapter on my host machine, which is set
> through Windows internet connection sharing (ICS) to go through my
> ethernet adapter.  I'm not seeing traffic on the TAP adapter, though,
> but nothing else I know of has an IP of 192.168.0.1.

Mike, either you use tap or user-net, these are mutually esclusive
approaches. If you use user-net you use slirp and you do not need any
TAP configuration or you use tap and the address must be given by a dhcp
server running on your host computer or just defined statically in a
consistent way.

ciao
	renzo