UML (UserModeLinux) networking problem

Hi Linuxers,

sorry to post this in 3 different news-groups, but I have no clou
which group would be the right one to ask.

I have a problem with UML and networking.
I try to setup a network connection between the UML virtuel machine
and the host but I don't get connection between them.

I can configure the eth0 device within UML using ifconfig and
I see the tap-device on the host. Seems to me, that the UML helper
programs (like uml_net) are working.
Both interfaces (UML and host) are up and routes are configured to the
devices with the apropriate network-addresses.

If I start tcpdump on both 'machines' and try pings between them, I
can see ARP-requests at the origin. But I don't receive any tcpdump
output at the destination and the target is unreachable.

What can I do/check to get the connection working ?
Could there be something missing within the host kernel ?

By the way, yes I know I can mount the host's filesystem on the UML
virual machine, but this is not what I want or need. I need the
possibility to initiate commands (e.g. via rsh) at the UML machine
from the/a host.

Any help/suggestion is welcome.

Thanks in advance
Guenter


The facts:

host-kernel: linux 2.4.18
UML-kernel: user_mode_linux-2.4.18.36um-0
executable downloaded form UML homepage (rpm package)
command on host: ping 192.169.10.10
command on UML: ping 192.168.10.100

ifconfig from host:
-------------------
eth0 Link encap:Ethernet HWaddr 00:04:76:EA:99:46
inet addr:129.23.12.160 Bcast:129.23.15.255 Mask:255.255.252.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5969070 errors:0 dropped:0 overruns:81 frame:0
TX packets:6075222 errors:0 dropped:0 overruns:0 carrier:0
collisions:691821 txqueuelen:100
RX bytes:2746909112 (2619.6 Mb) TX bytes:2242485986 (2138.6 Mb)
Interrupt:11 Base address:0x3400

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:21075 errors:0 dropped:0 overruns:0 frame:0
TX packets:21075 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1602048 (1.5 Mb) TX bytes:1602048 (1.5 Mb)

tap0 Link encap:Ethernet HWaddr FE:FD:00:00:00:00
inet addr:192.168.10.100 Bcast:192.168.10.255
Mask:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:148 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:17840 (17.4 Kb)
Interrupt:5


ifconfig from UML:
------------------
eth0 Link encap:Ethernet HWaddr FE:FD:C0:A8:0A:0A
inet addr:192.168.10.10 Bcast:192.168.10.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1484 Metric:1
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:28 (28.0 b) TX bytes:264 (264.0 b)
Interrupt:5

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:18 errors:0 dropped:0 overruns:0 frame:0
TX packets:18 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1628 (1.5 Kb) TX bytes:1628 (1.5 Kb)


route from host:
----------------
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.10.0 * 255.255.255.0 U 0 0 0 tap0
mchm_32 * 255.255.252.0 U 0 0 0 eth0
loopback * 255.0.0.0 U 0 0 0 lo
default mmma.ma. 0.0.0.0 UG 0 0 0 eth0

route from UML:
---------------
Destination Gateway Genmask Flags Metric Ref Use
Iface
192.168.10.0 * 255.255.255.0 U 0 0 0 eth0

G. Neumann wrote:
> If I start tcpdump on both 'machines' and try pings between them, I
> can see ARP-requests at the origin. But I don't receive any tcpdump
> output at the destination and the target is unreachable.

On the 'tap0' interface, the netmask value is specified as
'255.255.255.255'. Try changing the netmask value to '255.255.255.0' and
see if this change fixes the problem.

> tap0 Link encap:Ethernet HWaddr FE:FD:00:00:00:00
> inet addr:192.168.10.100 Bcast:192.168.10.255
> Mask:255.255.255.255
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:148 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:0
> RX bytes:0 (0.0 b) TX bytes:17840 (17.4 Kb)
> Interrupt:5

--
Jim

To reply by email, remove "link" and change "now.here" to "yahoo"
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In comp.os.linux.networking G. Neumann <(E-Mail Removed)> wrote:
> Hi Linuxers,
>
> sorry to post this in 3 different news-groups, but I have no clou
> which group would be the right one to ask.

The uml-user mailing list and the #uml channel on irc.usermodelinux.org
would be both topical and useful. Of course, that's not to say that this
forum would be a good choice too. ;^)

--
Cameron Kerr
(E-Mail Removed) : http://nzgeeks.org/cameron/
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