My setup: Private network vboxnet1 10.0.7.0/24 1 Host, ubuntu desktop 1 VM, ubuntu server (VirtualBox) Adressing layout: HOST: 10.0.7.1 VM: 10.0.7.101 VM MAC NAMESPACE: 10.0.7.102 On the VM, I ran the following commands: ip netns add mac # create a new nmespace ip link add link eth0 mac0 type macvlan # create a new macvlan interface ip link set mac0 netns mac On the mac namespace, inside the VM: ip link set lo up ip link set mac up ip addr add 10.0.7.102/24 dev mac0 So that we basically end up with: (Like Inception ?) +------------------------+ | Host: 10.0.7.1 | | | | +--------------------+ | | | VM: 10.0.7.101 | | | | | | | | +----------------+ | | | | | NS: 10.0.7.102 | | | | | | | | | | | +----------------+ | | | +--------------------+ | +------------------------+ What works: Ping between Host and VM Ping between NS and NS dhclient from NS What does not work: ping between NS and VM ping between NS and Host Where I started to go nuts: tcpdump on host (the real machine) actually shows ARP request AND replies tcpdump on NS shows ARP requests sent to the host tcpdump on VM makes the whole mess work (!) -- ping starts to get answers when tcpdump is started on the VM ?!? So, I bet you were eager for it, my question is: how to I make it work ? I suspect something's wrong with ARP on the macvlan inside the NS but can't figure out what exactly... Btw, I did the same expérimentations with the mac0 interface directly on the VM (no namespace) and it worked flawlessly.