Configuring Public IPv4 and IPv6 Addresses on a Cloud Server or Virtual Server with netplan (Ubuntu 22.04)

For Cloud Server and Virtual Private Server

This article explains how to add additional, public IPv4 and IPv6 addresses on a Cloud Server or Virtual Private Server that has Ubuntu 22.04 and netplan installed.

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

How to configure additional, public IPv4 and IPv6 addresses in Ubuntu 22.04:

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

• To check if the netplan.io package is installed on your Ubuntu or Debian system, enter the following command:

  [root@localhost ~]# dpkg -l | grep netplan.io

  If the netplan.io package is already installed, you will see information such as the following:

  root@localhost:~# dpkg -l | grep netplan.io
  ii netplan.io 0.105-0ubuntu2~22.04.3 amd64 YAML network configuration abstraction for various backends

• Change to the directory /etc/netplan.

  [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, enter the following command:

[root@localhost ~]# ip addr

In this example, the name of the network interface is ens192:

root@localhost:~# 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: ens192: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:50:56:08:a5:c6 brd ff:ff:ff:ff:ff:ff
    altname enp11s0
    inet 217.160.141.60/32 metric 100 scope global dynamic ens192
    inet6 2001:8d8:1801:5d2::1/64 scope global dynamic noprefixroute
       valid_lft 3443sec preferred_lft 3443sec
    inet6 fe80::250:56ff:fe08:a5c6/64 scope link
       valid_lft forever preferred_lft forever

• To display the DNS servers used, enter the following commands:

  [root@localhost ~]# curl http://169.254.169.254/latest/meta_data/dns/nameservers -Lv
  
  [root@localhost ~]# curl http://169.254.169.254/latest/meta_data/dns/nameservers6 -Lv

  Afterwards, the DNS servers used are displayed at the end of the output. Example:

  [root@localhost ~]# curl http://169.254.169.254/latest/meta_data/dns/nameservers -Lv
  * Trying 169.254.169.254...
  * TCP_NODELAY set
  * Connected to 169.254.169.254 (169.254.169.254) port 80 (#0)
  > GET /latest/meta_data/dns/nameservers HTTP/1.1
  > Host: 169.254.169.254
  > User-Agent: curl/7.61.1
  > Accept: */*
  >
  < HTTP/1.1 200 OK
  < Date: Thu, 08 Sep 2022 12:19:36 GMT
  < Server: Apache
  < Strict-Transport-Security: max-age=63072000; includeSubDomains
  < Vary: Accept-Encoding
  < Access-Control-Allow-Origin: *
  < Access-Control-Allow-Headers: X-TOKEN, X-HASH, X-MICROTIME, X-USER, Content-Type, X-API-TOKEN, Authorization
  < Access-Control-Allow-Methods: PUT, GET, POST, DELETE, OPTIONS
  < Access-Control-Expose-Headers: Error-Msg
  < Cache-control: no-cache, no-store, max-age=0
  < Access-Control-Allow-Origin: *
  < Access-Control-Allow-Headers: X-TOKEN, X-HASH, X-MICROTIME, Content-Type, X-API-TOKEN, Authorization
  < Access-Control-Allow-Methods: PUT, GET, POST, DELETE, OPTIONS
  < Access-Control-Expose-Headers: Error-Msg
  < Transfer-Encoding: chunked
  < Content-Type: text/plain;charset=UTF-8
  <
  212.227.123.16,212.227.123.17
  * Connection #0 to host 169.254.169.254 left intact.

• Make a note of the DNS servers. In the example above, the DNS servers are displayed above the line * Connection #0 to host 169.254.169.254 left intact.

• If the DNS server for IPv6 is not displayed, enter the following command:

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

  Example:

  root@localhost:/etc/netplan# resolvectl --no-pager |grep Server
  Current DNS Server: 212.227.123.16
         DNS Servers: 212.227.123.16 212.227.123.17 2001:8d8:fe:53:72ec::1

• To display the default gateway of the active interface, enter the following commands:
  
  IPv4:

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

  IPv6:

  [root@localhost ~]# ip -6 route show | grep 'default'

• Make a note of the IP addresses of the gateways. These are listed directly after the default via part. Examples:
  
  IPv4 gateway

  root@localhost:~# ip route show default
  default via 10.255.255.1 dev ens192 proto dhcp src 217.160.141.60 metric 100

  IPv6 gatewayroot@localhost

  :~# ip -6 route show | grep 'default'
  default via fe80::1 dev ens192 proto ra metric 100 expires 4sec pref high

  
  In this example, fe80::1 is the IPv6 gateway.

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

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

• If there is a configuration file in this directory, rename it. To do this, enter the following command and replace the placeholders.

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

• Create the file /etc/netplan/01-netcfg.yaml with the editor vi. 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_1/32
          - MAIN-IPv6-ADDRESS/64
          - ADDITIONAL IPv6-ADDRESS_1/64  
        gateway4: GATEWAY FOR IPv4
        nameservers:
          addresses:
            - IP-ADDRESS FOR NAMESERVER_1
            - IP-ADDRESS FOR NAMESERVER_2  
        routes:
          - to: default
            via: GATEWAY FOR IPv4
          - to: default
            via: GATEWAY FOR IPv6

  Example:

  network:
    version: 2
    renderer: networkd
    ethernets:
      ens192:
        addresses:
          - 85.215.105.86/32
          - 85.215.109.181/32
          - 2a01:239:0:805d::1/64
          - 2a01:239:0:805d::2/64
        gateway4: 10.255.255.1
        nameservers:
          addresses:
            - 212.227.123.16
            - 212.227.123.17
        routes:
          - to: default
            via: 10.255.255.1
          - to: default
            via: fe80::1

• Replace the placeholder NETWORKINTERFACE with the determined network interface. In the example above, the network interface is ens192. Then enter the main IPv4 address, the additional IPv4 addresses and and the main IPv6 address and the additional IPv6 addresses. Replace the placeholders shown above in caps.

• Replace the placeholder GATEWAY FOR IPv4 with the determined IPv4 gateway.

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

• Replace the placeholder GATEWAY FOR IPv6 with the determined IPv6 gateway.

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

• To change the permissions of the 01-netcfg.yaml file so only the root account can read and modify the file, type 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

• To avoid conflicts, it is necessary to uninstall ifupdown. To uninstall ifupdown and all other dependent packages and delete the configuration and/or data files of ifupdown, enter the following command:

  root@localhost:~# sudo apt-get autoremove --purge ifupdown

• 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

You can find more information about netplan in the following articles:

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

https://netplan.io/examples/