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

For Cloud Servers

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

The network configuration is carried out in the images of IONOS for Ubuntu 22.04 via netplan. The network configuration is no longer controlled via the /etc/network/interfaces file, but via files with the file extension .yaml, which are located in the /etc/netplan directory. If there are several 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 whether your server is already using 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 installed, you will see the following information, for example:

  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 /etc/netplan directory.

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

• Check whether there is already a configuration file in this directory. To do this, enter the following command:

  [root@localhost ~]# ls

Identify 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: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

  The DNS servers are then 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, Authorisation
  < 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, Authorisation
  < 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

• Note down the DNS servers. In the above example, 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'

   

• Note down 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 Gateway

  root@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 whether there is 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_CONFIGURATIONFILE.yaml OLD_CONFIGURATIONFILE.yaml.old

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

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

• Insert 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 OF NAMESERVER_1
  - IP ADDRESS OF 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 NETWORKINTERFACE placeholder with the network interface you identified. In the example above, this is the network interface ens192. Then enter the main IPv4 address, the additional IPv4 addresses and the main IPv6 address and the additional IPv6 addresses. To do this, replace the placeholders.

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

• Replace the placeholders IP ADDRESS FROM NAMESERVER 1 and IP ADDRESS FROM NAMESERVER 2 with the name servers you identified.

• Replace the placeholder GATEWAY FOR IPv6 with the IPv6 gateway you identified.

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

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

• To avoid conflicts, it is necessary that you 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

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

  root@localhost:~# systemctl reboot

• To check whether the additional IPv4 address has been configured correctly, enter the following command:

  root@localhost:~# ip addr

You can find more information about netplan here:

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

https://netplan.io/examples/

https://wiki.ubuntuusers.de/Netplan/