Adding Public IPv4 Addresses on a VPS (CentOS 7)

For IONOS VPS purchased after 16 May 2023

This article explains how to add additional, public IPv4 addresses on a VPS that has CentOS 7 installed.

These instructions are valid only for the VPS.

How to add IPv4 addresses and IPv6 addresses on a cloud server or vServer is described in the following article:

How to add IPv4 addresses and IPv6 addresses on a Dedicated Server is described in the following articles:

To configure another public IPv4 address in CentOS 7:

You assigned an additional, public IPv4 address to your server in the Cloud Panel.
You logged in to the server.
You made a note of the IPv4 addresses of the server.

Check the entries in the ifcfg-eth0 file. To do this, type the following command:
[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
Create an Ethernet alias and append a sequential number to the interface name, starting with 1 for the first alias. Thus, the first alias of eth0 is eth0:1. To create the /etc/sysconfig/network-scripts/ifcfg-eth0:1 file with the vi editor, enter the following command:
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0:1

The vi editor has an insert mode and a command mode. You can enter the insert mode by pressing the [i] key. In this mode, the entered characters are immediately inserted into the text. To enter the command mode, press [ESC] afterwards. When you use command mode, your keyboard input is interpreted as a command.
To exit vi and save the file, type the command :wq, and then press Enter.

To add an additional public IPv4 address to the network interface configuration, enter the following information:
DEVICE=eth0:1
Type=Ethernet
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
IPADDR=Additional IPv4 address
PREFIX=32
Example:
DEVICE=eth0:1
Type=Ethernet
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
IPADDR=123.456.789.12
PREFIX=32
Save the file.
Perform a reboot of the server. To do this, enter the following command:
[root@localhost ~]# reboot
The SSH connection is interrupted after you enter the command.
Log in to the server again.
To check if the additional public IPv4 address has been added, enter the following command:
[root@localhost ~]# ip addr
The additional public IPv4 address is then displayed. Example:
[root@ip82-165-34-29 ~]# 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 02:01:e9:29:97:0f brd ff:ff:ff:ff:ff:ff
inet 82.165.34.29/32 brd 82.165.34.29 scope global dynamic eth0
valid_lft 526sec preferred_lft 526sec
inet 195.20.236.17/32 brd 195.20.236.17 scope global eth0:1
valid_lft forever preferred_lft forever
inet6 fe80::1:e9ff:fe29:970f/64 scope link
valid_lft forever preferred_lft forever

If the server becomes unreachable due to a configuration error, you can log in to the server using the remote console and correct the configuration.