I am trying to route multiple IPs through one physical NIC on my dedicated server for use with Proxmox KVM VMs. I have a dedicated server which is currently running Debian 4.4.5-8 with 3 available ip addresses for use, which will be displayed as 176.xxx.xxx.196 (main), 176.xxx.xxx.198 (on same subnet as main) and 5.xxx.xxx.166 (different subnet). I am currently trying to route the third IP address with the dedi for use with a vps that I have set up using proxmox v2.x but am having a really, really hard time doing so. Virtual interfaces binding the additional IP addresses work as expected, ruling out external routing problems. The provider has given the following information for the IP addresses on the main subnet: gateway: 176.xxx.xxx.193 netmask: 255.255.255.224 broadcast: 176.xxx.xxx.223 As well as the following information for the IP address on the second subnet: gateway: 5.xxx.xxx.161 netmask: 255.255.255.248 broadcast: 5.xxx.xxx.167 Everything I've tried with /etc/network/interfaces has either not worked, or has rendered the network completely useless. This is the current state of the file, which has the secondary IP address working on the same subnet as well as IPv6 working, but not the second subnet. # Nativen IPv6 Schnittstelle iface eth0 inet6 manual # Bridge IPv4 Schnittstelle (176.xxx.xxx.193/27) auto vmbr0 iface vmbr0 inet static address 176.xxx.xxx.196 netmask 255.255.255.224 gateway 176.xxx.xxx.193 broadcast 176.xxx.xxx.223 bridge_ports eth0 bridge_stp off bridge_fd 0 bridge_maxwait 0 post-up ip addr add 176.xxx.xxx.198/27 dev vmbr0 auto vmbr1 iface vmbr1 inet static address 5.xxx.xxx.166 netmask 255.255.255.248 gateway 5.xxx.xxx.161 broadcast 5.xxx.xxx.167 bridge_ports eth0 bridge_stp off bridge_fd 0 bridge_maxwait 0 post-up ip addr add 5.xxx.xxx.166/27 dev vmbr1 # Bridge IPv6 Schnittstelle (Reichweite: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx::/64) iface vmbr0 inet6 static address xxxx:xxxx:xxxx:xxxx:xxxx:xxxx netmask 64 up ip -6 route add xxxx:xxxx:xxxx:xxxx:xxxx:xxxx dev vmbr0 down ip -6 route del xxxx:xxxx:xxxx:xxxx:xxxx:xxxx dev vmbr0 up ip -6 route add default via xxxx:xxxx:xxxx:xxxx:xxxx:xxxx dev vmbr0 down ip -6 route del default via xxxx:xxxx:xxxx:xxxx:xxxx:xxxx dev vmbr0