root@vps-uk:/etc/swanctl # cat /etc/network/interfaces.d/50-myvps-init
auto lo
iface lo inet loopback
        # CA
        dns-nameservers 158.69.126.137
        dns-nameservers 2607:5300:60:9389:15:2:a:1000
        dns-nameservers 2607:5300:60:9389:15:1:a:1000
        # DE
        dns-nameservers 2001:41d0:701:1100::6530
        dns-nameservers 135.125.133.51
        # OVH
        dns-nameservers 213.186.33.99

#auto ens3
iface ens3 inet manual

auto vmbr0
iface vmbr0 inet static
        address 57.128.171.43
        netmask 255.255.255.0
        broadcast 57.128.171.255
        gateway 57.128.170.1
        bridge-ports ens3
        bridge-stp off
        bridge-fd 0
        mtu 1500

iface vmbr0 inet6 static
        address 2001:41d0:801:2000::44f9
        netmask 128
        gateway 2001:41d0:801:2000::1
        mtu 1500
        post-up ip -6 addr change 2001:41d0:801:2000::44f9/128 dev vmbr0 preferred_lft 0

auto vmbr1
iface vmbr1 inet static
        address  10.171.43.254
        netmask  255.255.255.0
        bridge-ports none
        bridge-stp on
        bridge-fd 0
#       post-up ip -4 route add 10.171.43.0/24 via 10.171.43.1

iface vmbr1 inet6 static
        address fc00:41d0:801:2000::fffe
        netmask 64