Re: /dev/tun Was: Re: [Qemu-devel] Win98: how to exchange data with Linux

["Jim C. Brown" <jbrown106@phreaker.net>]

On Wed, Jul 14, 2004 at 09:10:01PM -0500, Joe Menola wrote:
> I'm baaaaaaaaaack. :)
> 
> I started playing with vbe, I think I've made some progress but can't seem to 
> get things working. It's possible that I'm in over my head.... I'll let you 
> be the judge.
> Here's where I'm at:
> 
> As root:
> [root@joe vde-1.5.3]# ./vde_switch -tap tap0 -daemon
> [root@joe vde-1.5.3]# ifconfig tap0 192.168.0.254
> [root@joe vde-1.5.3]# chmod 777 /tmp/vde.ctl
> [root@joe vde-1.5.3]# echo "1" > /proc/sys/net/ipv4/ip_forward
> [root@joe vde-1.5.3]#  iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
> 
> I assume that at this point vde is set and ready.... or have I already fallen 
> off the edge?
> 

The tap0 device should have its own subnet. E.g. below, it appears that your
LAN already uses the 192.168.0.* subnet. I'd recommend that you use this
ifconfig instead:

> [root@joe vde-1.5.3]# ifconfig tap0 192.168.254.254 netmask 255.255.255.0

I don't know iptables very well, but to the best of my knowledge that looks
correct. You can try adding this line as well, not sure if it will help or
not however:

> [root@joe vde-1.5.3]#  iptables -t nat -A POSTROUTING -o tap0 -j MASQUERADE

(note to self: add iptables guru to vde team)

> As user I start qemu with
> 
> [joe@joe qemu]$ vdeq qemu  -hda /mymnt/qemu/qdrive.img  -boot c -m 256 
> -enable-audio -pci -cirrusvga
> 
> Monitor output
> 
> QEMU 0.5.5 monitor - type 'help' for more information
> (qemu) qemu exited: vdeq quits
> [joe@joe qemu]$
> 

That looks right, unless you are saying that qemu quits prematurely.

> I'm somewhat confused about network settings for Win98, my "real" network 
> consists of my linux host (eth0) connected to a dsl router (192.168.0.1). 
> I tried dchp (my router supports it but it's not installed on my linux host), 
> tried static ip's 192.168.0.254 (address assinged to tap0?) and 192.168.0.135 
> (unused address on my lan) . As gateway's I have both my routers address and 
> eth0's address on my Linux host. Same for dns.
> No internet, and cannot ping anything.
> 
> Is there hope? lol

DHCP from the router will not work. Assuming that you've made the above change
and are using the 192.168.254.* subnet, the router/gateway for Win98 is
192.168.254.254 and you can assign it any ip address you want in the subnet,
for example 192.168.254.135 should work. You can also do

/sbin/dhcpd tap0

after you set up vde and install a DHCPd server. That works great for me.
(I can give you my dhcpd.conf file if you decide to go this route.)

> 
> -jm
> 
> 
> 
> 
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