auto dummy0
iface dummy0 inet static
    pre-up ip link add dummy0 type dummy
    address 192.168.141.1
    netmask 255.255.255.248
    post-down ip link del dummy0

auto veth0
iface veth0 inet static
    pre-up ip netns add clientnet
    pre-up ip link add veth0 type veth peer veth1 netns clientnet
    address 192.168.142.1
    netmask 255.255.255.248
    post-down ip link del veth0
    post-down ip netns del clientnet

iface veth1 inet dhcp