Adding Public IPv4 Addresses on a VPS (Ubuntu 20.04, 22.04 and Debian 12)

For VPSs purchased after May 16, 2023

This article explains how to add another public IPv4 address on a VPS that has Ubuntu 20.04, Ubuntu 22.04, or Debian 12 installed.

The network configuration is done through netplan in the images of IONOS for Ubuntu 20.04 and Ubuntu 22.04. Network configuration is no longer controlled by the /etc/network/interfaces file but by files with the .yaml file extension that are located in the /etc/netplan directory. If there are multiple files in this directory, they are loaded in lexical order.

To configure another public IPv4 address in Ubuntu 20.04 and 22.04:

To check if your server is already using netplan for network configuration, enter the following command:

• Change to the /etc/netplan directory.

  [root@localhost ~]# cd /etc/netplan

• Check if there is not already a configuration file in this directory. To do this, enter the following command:

  [root@localhost ~]# ls

Determine the file name of the network interface. To do this, type the following command:

[root@localhost ~]# ip addr

In this example, the network interface name is ens6:

root@ubuntu:/etc/netplan# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: ens6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 02:01:e4:95:f5:d9 brd ff:ff:ff:ff:ff:ff
    inet 195.20.234.94/32 scope global dynamic ens6
       valid_lft 463sec preferred_lft 463sec
    inet6 fe80::1:e4ff:fe95:f5d9/64 scope link
       valid_lft forever preferred_lft forever

To display the DNS servers used, enter the following command:

[root@localhost ~]# resolvectl --no-pager |grep Server

Then, the DNS servers used are displayed at the end of the output.

Example:

[root@localhost ~]# resolvectl --no-pager |grep Server
Current DNS Server: 212.227.123.16
       DNS Servers: 212.227.123.16 212.227.123.17

Make a note of the DNS servers.

• To display the default gateway of the active interface, enter the following command:

  [root@localhost ~]# ip route show | grep 'default'

• Note the IP addresses of the gateways. These are listed directly after the default via part. Example:

  IPv4 gateway

  root@ubuntu:~# ip route show | grep 'default'
  default via 195.20.234.1 dev ens6 proto dhcp src 195.20.234.94 metric 100

• Check if there is not already a configuration file in this directory. To do this, enter the following commands:

  [root@localhost ~]# cd /etc/netplan
  [root@localhost ~]# ls /etc/netplan

• If there is a configuration file in this directory, rename it. To do this, type the following command and replace the wildcards (OLD_CONFIG_FILE).

  root@localhost ~]# mv OLD_CONFIG_FILE.yaml OLD_CONFIG_FILE.yaml.old

  Example:

  [root@localhost ~]# mv 50-cloud-init.yaml 50-cloud-init.yaml.old

• Create the /etc/netplan/01-netcfg.yaml file using the vi editor. To do this, enter the following command:

  [root@localhost ~]# vi etc/netplan/01-netcfg.yaml

• Include the following information:

  network:
    version: 2
    renderer: networkd
    ethernets:
      NETWORKINTERFACE:
        addresses:
          - MAIN-IPv4-ADDRESS/32
          - ADDITIONAL IPv4-ADDRESS/32 
        nameservers:
          addresses:
            - IP ADDRESS FROM NAMESERVER 1
            - IP ADDRESS FROM NAMESERVER 2  
        routes:
          - on-link: true
            to: default
            via: STANDARD-GATEWAY OF ACTIVE INTERFACE
    version: 2

  Example:

  network:
    version: 2
    renderer: networkd
    ethernets:
      ens6:
        addresses:
          - 195.20.234.94/32
          - 195.20.234.86/32
        nameservers:
          addresses:
            - 212.227.123.16
            - 212.227.123.17  
        routes:
          - on-link: true
            to: default
            via: 195.20.234.1
    version: 2

• Replace the placeholder NETWORKINTERFACE with the interface device ens192. Then enter the main IPv4 address and the additional IPv4 address. Replace the placeholders for this.

• Replace the placeholder IP ADDRESS OF NAME SERVER 1 and IP ADDRESS OF NAME SERVER 2 with the determined name servers.

• Replace the placeholder STANDARD-GATEWAY OF ACTIVE INTERFACE with the determined IPv4 gateway.

• To exit vi and save the file, type the command :wq and then press Enter.

• To change the permissions of the 01-netcfg.yaml file so that only the root account can read and modify the file, enter the following command:

  root@localhost:~# sudo chmod 600 /etc/netplan/01-netcfg.yaml

• To check the configuration file, enter the following command:

  root@localhost:~# netplan --debug apply

• Reboot the server to apply the changes. To do this, enter the following command:

  root@localhost:~# systemctl reboot

• To verify that the additional IPv4 address is configured correctly, enter the following command:

  root@localhost:~# ip addr

Additional Information

You can find more information about netplan here:

http://manpages.ubuntu.com/manpages/bionic/man5/systemd.network.5.html

https://netplan.io/examples/