auto lo
iface lo inet loopback

auto vmbr0
iface vmbr0 inet static
    address xxx.xxx.xxx.2
    netmask 255.255.255.0
    gateway xxx.xxx.xxx.1
    bridge_ports eth2
    bridge_stp off
    bridge_fd 0

iface vmbr0 inet6 static
    address 2604:xxxx:xxxx:xxxx:0000:0000:0000:0003
    netmask 128
    gateway 2604:xxxx:xxxx:xxxx:0000:0000:0000:0001

2604:xxxx:x:x::3 dev vmbr0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
fe80::1 dev venet0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
fe80::/64 dev venet0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
fe80::/64 dev eth2  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0
fe80::/64 dev vmbr0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 0

RTNETLINK answers: No route to host

connect: Network is unreachable