[Qemu-discuss] Networking Problems with Debian Stretch + KVM + old Linux Guest

[Hermann Himmelbauer]

Hi,
I today upgraded my KVM host from Debian 8 to the latest Debian 9
(Stretch). This worked perfectly, however, 2 old guest systems (SuSE
9.1, kernel 2.6.7 / 2.6.5) have no network access.

All other machines running on this host are Linux Debian machines and
use the "virtio" networking drivere whereas those two old machines use
RTL8139 (or e1000, makes no difference).

On the guest side, the networking interface (eth0 / rtl8139) is up, it
states "Link Up / 100MBit" in the log file, everything looks fine, but I
can't get out, no ping, empty arp table etc.

Basically, I use bridging for the virtual hosts, this looks like this:

br0             8000.0026186273f4       no              eth0
                                                        vnet0
                                                        vnet1

or like so:

port no mac addr                is local?       ageing timer
  1     00:00:24:cc:c7:85       no                 0.42
  1     00:19:66:b3:cb:34       no                 3.97
  1     00:22:b0:cf:04:b2       no                 0.03


What is interesting is that I cannot find the MAC Address of the 2
machines in the above table, which is probably not good.

Forwarding is enabled for all bridges and there is no packet filter /
firewall.

I have no clue how to solve this problem - do you have any idea?

Best Regards,
Hermann

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