> I don't know how the virtio-net-pci device works, but for other > network devices I guess you should also set different MAC addresses > for them. If you use an DHCP server it might give the same IP address > to both devices. > ...I actually suspect that QEMU (or the Linux kernel?) invents unique MAC addresses for the VM guest emulated NIC's... otherwise you'd see the warning in every tutorial, to set a unique MAC by hand.
And if the MAC addresses used by the VM guests were in fact indeed overlapping with each other, and possibly with the host, you'd get a problem with *ARP* even if DHCP is not in the game... It should be trivial for the OP to learn the MAC address used by each VM guest. Just issue an ifconfig or "ip link show" inside the VM guest OS instance. And there are possibly other ways, such as using the qemu monitor command line or virsh... or just checking the BIOS SETUP inside the VM, or watching its PXE bootrom messages right after POST... Frank https://documentation.suse.com/de-de/sles/15-SP6/html/SLES-all/cha-qem u-monitor.html
