Debian 11
By default, the configuration files are located in /etc/network/interfaces.d/. We recommend that you start by backing up the relevant configuration file.
Step 1: Create a backup
In our example, our file is called 50-cloud-init, so we make a copy of the 50-cloud-init file using the following command:
sudo cp /etc/network/interfaces.d/50-cloud-init /etc/network/interfaces.d/50-cloud-init.bak
In case of a mistake, you will be able to revert the changes, using the commands below:
sudo rm -f /etc/network/interfaces.d/50-cloud-init
sudo cp /etc/network/interfaces.d/50-cloud-init.bak /etc/network/interfaces.d/50-cloud-init
Step 2: Edit the configuration file
Info
Note that the names of the network interfaces in our examples may differ from your own. Please adjust to your appropriate interface names.
You can now modify the configuration file:
sudo nano /etc/network/interfaces.d/50-cloud-init
Next, you need to add a virtual interface or ethernet alias. In our example, our interface is called eth0, so our alias is eth0:0. Do this for each additional IP you wish to configure.
Do not modify the existing lines in the configuration file, simply add your Additional IP to the file as follows, replacing ADDITIONAL_IP/32 as well as the virtual interface (if your server is not using eth0:0) with your own values:
auto eth0:0
iface eth0:0 inet static
address ADDITIONAL_IP
netmask 255.255.255.255
Alternatively, you can configure your Additional IP by adding the following lines in the configuration file:
post-up /sbin/ifconfig eth0:0 ADDITIONAL_IP netmask 255.255.255.255 broadcast ADDITIONAL_IP
pre-down /sbin/ifconfig eth0:0 down
With the configuration above, the virtual interface is enabled or disabled whenever the eth0 interface is enabled or disabled.
If you have two Additional IPs to configure, the /etc/network/interfaces.d/50-cloud-init file should look like this:
auto eth0
iface eth0 inet dhcp
auto eth0:0
iface eth0:0 inet static
address ADDITIONAL_IP1
netmask 255.255.255.255
auto eth0:1
iface eth0:1 inet static
address ADDITIONAL_IP2
netmask 255.255.255.255
Or like this:
auto eth0
iface eth0 inet dhcp
# IP 1
post-up /sbin/ifconfig eth0:0 ADDITIONAL_IP1 netmask 255.255.255.255 broadcast ADDITIONAL_IP1
pre-down /sbin/ifconfig eth0:0 down
# IP 2
post-up /sbin/ifconfig eth0:1 ADDITIONAL_IP2 netmask 255.255.255.255 broadcast ADDITIONAL_IP2
pre-down /sbin/ifconfig eth0:1 down
Configuration example
auto eth0
iface eth0 inet dhcp
auto eth0:0
iface eth0:0 inet static
address 203.0.113.1
netmask 255.255.255.255
Or:
auto eth0
iface eth0 inet dhcp
# IP 1
post-up /sbin/ifconfig eth0:0 203.0.113.1 netmask 255.255.255.255 broadcast 203.0.113.1
pre-down /sbin/ifconfig eth0:0 down
Step 3: Restart the interface
To restart the interface, use the following command:
sudo /etc/init.d/networking restart
Fedora 42 and following, AlmaLinux & Rocky Linux (10)
Fedora now uses keyfiles. NetworkManager previously stored network profiles in ifcfg format in this directory: /etc/sysconfig/network-scripts/. However, the ifcfg format is now deprecated. By default, NetworkManager no longer creates new profiles in this format. The configuration file is now found in /etc/NetworkManager/system-connections/.
Step 1: Create a backup
Info
Note that the name of the network file in our example may differ from your own. Please adjust to your appropriate name.
First, make a copy of the configuration file, so that you can revert at any time. In our example, our configuration file is called cloud-init-eno1.nmconnection.
sudo cp -r /etc/NetworkManager/system-connections/cloud-init-eno1.nmconnection /etc/NetworkManager/system-connections/cloud-init-eno1.nmconnection.bak
Step 2: Edit the config file
Info
Please note that the name of the network file in our example may differ from yours. Please adapt the commands to your file name.
To obtain the name of your network interface in order to edit the appropriate network file, you can run one of the following commands:
Do not modify the existing lines in the configuration file, add your Additional IP to the file as follows, replacing ADDITIONAL_IP/32 with your own values:
sudo nano /etc/NetworkManager/system-connections/cloud-init-eno1.nmconnection
[ipv4]
method=auto
may-fail=false
address1=ADDITIONAL_IP/32
If you have two Additional IPs to configure, the configuration should look like this:
[ipv4]
method=auto
may-fail=false
address1=ADDITIONAL_IP1/32
address2=ADDITIONAL_IP2/32
Configuration example
[ipv4]
method=auto
may-fail=false
address1=203.0.113.1/32
Step 3: Restart the interface
You now need to restart your interface:
sudo systemctl restart NetworkManager
Debian 12, Ubuntu 20.04 and following
By default, the configuration files are located in the /etc/netplan directory.
The best practice approach is to create a separate configuration file to set up Additional IP addresses. This way, you can easily revert the changes in case of an error.
Step 1: Determine the interface
Note the name of the interface (the one on which your server's main IP address is configured).
Step 2: Create and edit the configuration file
Next, create a configuration file with a .yaml extension. In our example, our file is called 51-cloud-init.yaml.
sudo nano /etc/netplan/51-cloud-init.yaml
Edit the file with the content below, replacing INTERFACE_NAME and ADDITIONAL_IP with your own values:
network:
version: 2
ethernets:
INTERFACE_NAME:
dhcp4: true
addresses:
- ADDITIONAL_IP/32
If you have two Additional IPs to configure, the configuration file should look like this:
network:
version: 2
ethernets:
INTERFACE_NAME:
dhcp4: true
addresses:
- ADDITIONAL_IP1/32
- ADDITIONAL_IP2/32
Warning
It is important to respect the alignment of each element in this file as represented in the example above. Do not use the tab key to create your spacing. Only the space key is needed.
Configuration example
network:
version: 2
ethernets:
eth0:
dhcp4: true
addresses:
- 203.0.113.1/32
Save and close the file. You can test the configuration with the following command:
Step 3: Apply the change
If it is correct, apply it using the following command:
Info
When using the netplan try command, it is possible that the system returns a warning message such as Permissions for /etc/netplan/xx-cloud-init.yaml are too open. Netplan configuration should NOT be accessible by others. This simply means that the file does not have restrictive permissions. This does not affect the configuration of your Additional IP. For more information about file permissions, consult the official documentation of ubuntu.
AlmaLinux (8/9) & Rocky Linux (8/9)
The main configuration file is located in /etc/sysconfig/network-scripts/. In this example it is called ifcfg-eth0. Before making changes, verify the actual file name in this folder.
For each Additional IP to be configured, we create a separate configuration file with the following parameters: ifcfg-NETWORK_INTERFACE:ID. Where NETWORK_INTERFACE is the physical interface and ID is the virtual network interface or ethernet alias starting with a value of 0. For example, for our interface named eth0 the first alias is eth0:0, the second alias is eth0:1, etc...
Step 1: Determine the interface
Note the name of the interface (the one on which your server's main IP address is configured).
Step 2: Create the configuration file
First, create the configuration file. Replace NETWORK_INTERFACE:ID with your own values.
sudo nano /etc/sysconfig/network-scripts/ifcfg-NETWORK_INTERFACE:ID
Next, edit the file with the content below, replacing NETWORK_INTERFACE:ID, and ADDITIONAL_IP with your own values:
DEVICE=NETWORK_INTERFACE:ID
ONBOOT=yes
BOOTPROTO=none # For CentOS use "static"
IPADDR=ADDITIONAL_IP
NETMASK=255.255.255.255
BROADCAST=ADDITIONAL_IP
Configuration example
DEVICE=eth0:0
ONBOOT=yes
BOOTPROTO=none # For CentOS use "static"
IPADDR=203.0.113.1
NETMASK=255.255.255.255
BROADCAST=203.0.113.1
Step 3: Restart the interface
Next, restart the network interface with the following command:
sudo systemctl restart NetworkManager
cPanel
Step 1: Access the WHM IP management section
In the WHM control panel, click on IP Functions and select Add a New IP Address in the left-hand sidebar.
Step 2: Add the Additional IP information
Enter your Additional IP in the form xxx.xxx.xxx.xxx into the field “New IP or IP range to add”.
Select 255.255.255.255 as your subnet mask, then click on Submit.
Warning
Please note that if you have more than one IP to configure on the same block and you add them all at once, the WHM system will force you to use the subnet mask 255.255.255.0. We do not recommend using this configuration. Instead, you need to add each IP individually in order to use the proper subnet mask 255.255.255.255.
Step 3: Check the current IP configuration
Back in the section IP Functions, click on Show or Delete Current IP Addresses to verify that the Additional IP address was added correctly.
Windows Servers
Windows servers are often DHCP-enabled in the network configuration. If you have already set up an Additional IP or switched your configuration to a fixed IP, go directly to the next step.
Otherwise, you need to first switch from a network-level DHCP configuration to a fixed IP configuration.
Open the command prompt cmd or powershell, then type the following command:
This will return a result similar to the following example:
Identify and write down your IPv4, subnet mask, default gateway and the name of the network interface controller (network adapter).
In our example, the server IP is 192.0.2.28.
You can perform the next steps via either a command-line interface or the graphical user interface.
Via a command-line interface (recommended)
In the commands below, you need to replace:
Warning
Be careful – the server will no longer be accessible if you enter incorrect information. You will then have to make the corrections in Winrescue mode or via the IPMI.
In the command prompt:
1. Switch to a fixed IP
netsh interface ipv4 set address name="NETWORK_ADAPTER" static IP_ADDRESS SUBNET_MASK GATEWAY
2. Set the DNS server
netsh interface ipv4 set dns name="NETWORK_ADAPTER" static 213.186.33.99
3. Add an Additional IP
netsh interface ipv4 add address "NETWORK_ADAPTER" ADDITIONAL_IP 255.255.255.255
Your Additional IP is now functional.
Via the graphical user interface
- Go to
Start > Control Panel > Network and Internet > Network and Sharing Centre > Change Adapter Settings (in the left-hand menu).
- Right-click on your network connection, in our example
Ethernet 2.
- Click on
Properties.
- Select
Internet Protocol Version 4 (TCP/IPv4), then click on Properties.
- Click on
Use the following IP address and type in your server’s primary IP, subnet mask and default gateway information obtained by using the ipconfig command above. In the "Preferred DNS Server" box, type 213.186.33.99.
Warning
Be careful – the server will no longer be accessible if you enter incorrect information. You will then have to make the corrections in Winrescue mode or via the IPMI.
Then click on Advanced (still in the TCP/IP Settings).
In the IP Address section, click Add:
Type in your Additional IP and the subnet mask 255.255.255.255. Then click on Add
Click on OK to apply your configuration.
Your Additional IP is now functional, you can verify the configuration with the following command:
This will return a result similar to the following example:
Plesk
Step 1: Access the Plesk IP management section
In the Plesk control panel, choose Tools & Settings from the left-hand sidebar.
Click on IP Addresses under Tools & Resources.
Step 2: Add the Additional IP information
In this section, click on the button Add IP Address.
Enter your Additional IP in the form xxx.xxx.xxx.xxx/32 into the field "IP address and subnet mask", then click on OK.
Step 3: Check the current IP configuration
Back in the section "IP Addresses", verify that the Additional IP address was added correctly.
