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Configure Additional IP Addresses

If your server needs to be reachable on more than one IPv4 address, you can add additional addresses to your existing network interface.

Prerequisites​

Netplan​

Open /etc/netplan/55-interfaces.yaml in your preferred editor:

vi /etc/netplan/55-interfaces.yaml

And add the additional IP address under addresses:

bonds:
  bond0:
    addresses:
      - 198.51.100.10/24
      - 198.51.100.11/24

A complete Netplan configuration could look like this:

network:
  version: 2
  ethernets:
    eno1:
      dhcp4: false
      dhcp6: false
      accept-ra: false
    eno2:
      dhcp4: false
      dhcp6: false
      accept-ra: false
  bonds:
    bond0:
      addresses:
        - 198.51.100.10/24
        - 198.51.100.11/24
      nameservers:
        addresses:
          - 217.150.241.5
          - 217.150.242.21
          - 178.209.45.7
        search:
          - nine.ch
      macaddress: 1f:2f:3f:4f:5f:6f # MAC address of the first interface (eno1)
      interfaces:
        - eno1
        - eno2
      parameters:
        mode: "802.3ad"
        mii-monitor-interval: "100"
        lacp-rate: "fast"
        transmit-hash-policy: "layer3+4"
      routes:
        - to: 0.0.0.0/0
          via: 198.51.100.1

Before applying the Netplan configuration, test it to ensure there are no syntax errors or network issues:

netplan try

If the test was successful and the configuration hasn't been applied yet using netplan try, apply it now:

netplan apply

And verify with:

ip -4 addr show bond0

For more information, see: man netplan

ifupdown (legacy)
tip

Please use Netplan if possible. This is provided for completeness only.

Open /etc/network/interfaces in your preferred editor:

vi /etc/network/interfaces

Add the additional IP address(es):

auto bond0
iface bond0 inet static
    hwaddress ether 1f:2f:3f:4f:5f:6f
    address 198.51.100.10
    netmask 255.255.255.0
    gateway 198.51.100.1
    bond_slaves eno1 eno2
    bond_primary eno1
    bond_mode 4
    bond_miimon 100
    bond_xmit_hash_policy layer3+4
    bond_lacp_rate 1
    # Add secondary IP address
    up ip addr add 198.51.100.11/24 dev bond0 || true

And restart the network:

systemctl restart networking

For more information, see: man interfaces