Am 21.01.2018 um 10:53 schrieb Binarus: > On 20.01.2018 17:04, Hermann Himmelbauer wrote: >> 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. > > I had a similar problem some years ago. In my case, the network in the > guests generally worked, but was stuttering such extremely that it > actually could not be used. > > After some research, it turned out that I had to assign a MAC address to > the guests' (virtual) NICs explicitly. > > You haven't told us how you configure / start your VMs. I personally > don't use libvirt and colleagues, but I am starting the VMs from the > command line. Consequently, I don't know how to assign MAC addresses > using the high-level configuration tools. What I am doing on the command > line (as far as it concerns the network) is something like that (please > imagine the following code to be on one line): > > /usr/bin/qemu-system-x86_64 > [...] > -device virtio-net-pci,vlan=0,mac=02:01:01:01:02:01 > -net > tap,vlan=0,name=dax,ifname=dax0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown > [...] > > Please note how the MAC address is explicitly assigned. script and > downscript are just two simple wrappers which add the virtual NIC to an > existing bridge which connects them with the host and the other VMs. > > The disadvantage of this method is that you have to manage the MAC > addresses yourself (you ultimately must make sure that every VM gets its > own and that no other device in the world (in practice in most cases: in > your network) has the same as one of your virtual NICs). The MAC address > shown above is from the semi-official private MAC address space, so I am > hopefully out of trouble in this respect. > > Please let us know if this solves your problem. O.k., just got it running - I upgraded the machine from kernel 2.6.7 to 2.6.27 and now it works - also with the rtl8139 driver. So it seems that networking of QEMU/KVM has some problems with old Linux kernels - I did not investigate this further, however. Best Regards and thanks for help, Hermann -- hermann@xxxxxxx PGP/GPG: 299893C7 (on keyservers)
