IP aliasing is a special network configuration for your OVHcloud servers which allows you to associate multiple IP addresses with a single network interface. In this article, we will walk through how to configure IP aliasing on your VPS.
Requirements
- A virtual private server on your OVHcloud account
- An Additional IP address or an Additional IP block
- Administrative access (root) via SSH or GUI to your server
- Basic networking and administration knowledge
Instructions
The following sections contain the configurations for the most commonly used distributions/operating systems. The first step is always to log in to your server via SSH or a GUI login session (RDP for a Windows VPS). The examples below presume you are logged in as a user with elevated permissions (Administrator/sudo).
Please take note of the following terminology that will be used in code examples and instructions of the guide sections below:
| Term | Description | Examples |
| ADDITIONAL_IP | An Additional IP address assigned to your service | 169.254.10.254 |
| NETWORK_INTERFACE | The name of the network interface | eth0, ens3 |
| ID | ID of the IP alias, starting with 0 (depending on the number of additional IPs there are to configure) | 0, 1 |
Debian 10/11
Step 1: Disable automatic network configuration
Open the following file path with a text editor:
sudo nano /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg
Enter the following line, then save and exit the editor:
network: {config:disabled}
Creating this configuration file will prevent changes to your network configuration from being made automatically.
Step 2: Edit the network configuration file
You can verify your network interface name with this command:
ip a
Open the network configuration file for editing with the following command:
sudo nano /etc/network/interfaces.d/50-cloud-init.cfg
Then add the following lines:
auto NETWORK_INTERFACE:ID
iface NETWORK_INTERFACE:ID inet static
address ADDITIONAL_IP
netmask 255.255.255.255
Step 3: Restart the interface
Apply the changes with the following command:
sudo systemctl restart networking
Ubuntu 20.04 & Debian 12
The configuration file for your Additional IP addresses is located in /etc/netplan/. In this example, it is called "50-cloud-init.yaml". Before making changes, verify the actual file name in this folder. Each Additional IP address will need its own line within the file.
Step 1: Disable automatic network configuration
Open the following path with a text editor:
ip a
Enter the following line, then save and exit the editor:
network: {config: disabled}
Creating this configuration file will prevent changes to your network configuration from being made automatically.
Step 2: Edit the configuration file
You can verify your network interface name with this command:
sudo nano /etc/netplan/50-cloud-init.yaml
Do not modify the existing lines of the configuration file. Add your Additional IP address by adding a second configuration block for the public interface according to the example below.
network:
version: 2
ethernets:
NETWORK_INTERFACE:
dhcp: true
match:
macaddress: fa:xx:xx:xx:xx:63
set-name: NETWORK_INTERFACE
NETWORK_INTERFACE:
dhcp: true
match:
macaddress: fa:xx:xx:xx:xx:63
set-name: NETWORK_INTERFACE
addresses:
- ADDITIONAL_IP/32
Save and close the file.
Step 3: Apply the new network configuration
You can test your configuration using this command:
sudo netplan try
If it is correct, apply it using the following command:
sudo netplan apply
Repeat this procedure for each Additional IP address.
Windows Server 2016
Step 1: Verify the network configuration
Right-click on the Start Menu button and open Run.
Type cmd and click OK to open the command line application.
To retrieve the current IP configuration, enter ipconfig at the command prompt.
Step 2: Change the IPv4 Properties
Now you need to change the IP properties to a static configuration.
Open the adapter settings in the Windows control panel and then open the Properties of Internet Protocol Version 4 (TCP/IPv4).
In the IPv4 Properties window, select Use the following IP address. Enter the IP address that you retrieved in the first step, then click on Advanced.
Step 3: Add the Additional IP in the "Advanced TCP/IP Settings"
In the new window, click on Add... under "IP addresses". Enter your Additional IP address and the subnet mask (255.255.255.255).
Confirm by clicking on Add.
Step 4: Restart the network interface
Back in the control panel (Network Connections), right-click on your network interface and then select Disable.
To restart it, right-click on it again and then select Enable.
Step 5: Check the new network configuration
Open the command prompt (cmd) and enter ipconfig. The configuration should now include the new Additional IP address.
cPanel (CentOS 7) / Red Hat derivatives
Step 1: Edit the network configuration file
You can verify your network interface name with this command:
ip a
Open the network configuration file for editing:
sudo nano /etc/sysconfig/network-scripts/ifcfg-NETWORK_INTERFACE:ID
Then add these lines:
DEVICE=NETWORK_INTERFACE:ID
BOOTPROTO=static
IPADDR=ADDITIONAL_IP
NETMASK=255.255.255.255
BROADCAST=ADDITIONAL_IP
ONBOOT=yes
Step 2: Restart the interface
Apply the changes with the following command:
sudo systemctl restart networking
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.
Troubleshooting
First, restart your server from the command line or its GUI. If you are still unable to establish a connection from the public network to your alias IP and suspect a network problem, you need to reboot the server in rescue mode. Then you can set up the Additional IP address directly on the server.
Once you are connected to your server via SSH, enter the following command:
ifconfig ens3:0 ADDITIONAL_IP netmask 255.255.255.255 broadcast ADDITIONAL_IP up
To test the connection, simply ping your Additional IP from the outside. If it responds in rescue mode, that probably means that there is a configuration error. If, however, the IP is still not working, please inform our support teams by creating a support request in your OVHcloud Control Panel for further investigations.
Go further
For more information and tutorials, please see our other Virtual Private Server support guides or explore the guides for other OVHcloud products and services.