Re: [Qemu-devel] Help with tun/tap with qemu

["Jesus M. Salvo Jr." <jesus.salvo@migasia.com>]

Jesus M. Salvo Jr. wrote:

> Antony T Curtis wrote:
>
>> On Tue, 2004-08-10 at 16:50, Bartosz Fabianowski wrote:
>>  
>>
>>>> So I am trying TUN/TAP.  The guest and host OS can ping each other.
>>>> However, the guest OS cannot ping any other host
>>>>     
>>>
>>> If the setup on Linux is any similar to that on FreeBSD (and I am 
>>> sure it is), the problem probably is routing. The guest and host are 
>>> on different networks. So, you need to tell your host to forward 
>>> packets to and from the guest's network. You didn't have that 
>>> problem in slirp, because slirp bridges between the two networks for 
>>> you, it implicitly does the forwarding.
>>>
>>> Unfortunately, I can't tell you how to add the route under Linux due 
>>> to my lack of experience with that platform.
>>>
>>> - Bartosz
>>>   
>>
>>
>> When I am using TAP on FreeBSD, I use ng_bridge so the guest is on the
>> same network as the host.
>>
>> Info for configuring ng_bridge is in
>> /usr/share/examples/netgraph/ether.bridge
>>
>>  
>>
> OK, I have now setup a bridge on linux as follows.
> On the host OS, I have the following script and ran it as root:
>
> #!/bin/sh
> /usr/sbin/brctl addbr br0
> /sbin/ifconfig eth2 0.0.0.0 promisc up
> /sbin/ifconfig tap0 0.0.0.0 promisc up
> /sbin/ifconfig br0 192.168.0.199 netmask 255.255.255.0 broadcast 
> 192.168.0.255 up
> /usr/sbin/brctl stp br0 off
> /usr/sbin/brctl setfd br0 1
> /usr/sbin/brctl sethello br0 1
> /usr/sbin/brctl addif br0 eth2
> /usr/sbin/brctl addif br0 tap0
> /sbin/route add default gw 192.168.0.1
>
> I can confirm that the host still has network connectivity using the 
> bridge.
>
> Now the question is, what to do on the qemu side ?? 

Not clear enough.
What I have done so far on the guest OS side is:

/sbin/ifconfig eth0 192.168.0.98 up
/sbin/route add default gw 192.168.0.1

However, the host and guest OS could not ping each other.

Also, how does one setup a bridge in the case where one only has a 
dial-up modem to the ISP, where all I have on the host OS is a ppp 
interface ?