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. Regards, Binarus
