Adding an additional IP is routine for any system administrator. When you set up a new server, it will have a single IP address linked with the server hostname. There are several reasons you might need to set up an additional IP address on your system. Some of them are listed below:
- To set up Internet sharing with Squid proxy server.
- To run the same service multiple times.
- To use different hostnames in reverse DNS lookups.
- To avoid being blacklisted in spam filters.
- To host multiple SSL sites.
Ubuntu allows you to add multiple virtual IP addresses on a single network interface card without buying an additional network adapter.
In this tutorial, we will explain how to add an additional IP address on an Ubuntu 18.04 server.
Prerequisites
- A fresh Ubuntu 18.04 VPS on the Atlantic.Net Cloud Platform.
- A reserved additional IP. You can find out how to reserve an additional IP here.
Create an Atlantic.Net Cloud Server
First, log in to your Net Cloud Server. Create a new server, choosing Ubuntu 18.04 as the operating system with at least 2GB RAM. Connect to your Cloud Server via SSH and log in using the credentials highlighted at the top of the page.
Once you are logged into your Ubuntu 18.04 server, run the following command to update your base system with the latest available packages.
apt-get update -y
Add an Additional IP Address Permanently
The process to configure an IP address on an Ubuntu 18.04 server is different than the older method used in the older version of Ubuntu. Ubuntu 18.04 uses Netplan utility to configure networking.
You can add an additional IP address permanently to your system by editing the file /etc/netplan/50-cloud-init.yaml.
First, you can see your existing IP address with the following command:
ip addr
You should see the following output:
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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 08:00:27:c8:48:62 brd ff:ff:ff:ff:ff:ff inet 192.168.0.101/24 brd 192.168.0.255 scope global enp0s3 valid_lft forever preferred_lft forever inet6 fe80::a00:27ff:fec8:4862/64 scope link valid_lft forever preferred_lft forever
You can also see your existing network configuration with the following command:
cat /etc/netplan/50-cloud-init.yaml
You should see your existing network configuration in the following output:
# This file is generated from information provided by
# the datasource. Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
version: 2
ethernets:
enp0s3:
dhcp4: no
addresses: [192.168.0.101/24]
gateway4: 192.168.0.1
nameservers:
addresses: [8.8.8.8]
In the above output, you should see that the IP address 192.168.0.101 is assigned to the interface.
Here’s a brief explanation of each parameter:
- enp0s3: A device name to be configured.
- dhcp4: Used to enable or disable dhcp4.
- dhcp6: Used to enable or disable dhcp6.
- addresses: The IP address of the device.
- gateway4: The IP address of your gateway.
- nameservers: The IP address of your DNS server.
Next, we will add an additional IP address 192.168.0.100 to the server.
To do so, open your file /etc/netplan/50-cloud-init.yaml in your preferred text editor:
nano /etc/netplan/50-cloud-init.yaml
After adding an additional IP address, your file should look something like this:
network: version: 2 ethernets: enp0s3: dhcp4: no addresses: [192.168.0.101/24, 192.168.0.100/24] gateway4: 192.168.0.1 nameservers: addresses: [8.8.8.8]
Save and close the file when you are finished. Then, enable the new configuration with the following command:
netplan apply
Now, check your new IP address with the following command:
ip addr
You should see both IP addresses in the following output:
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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 08:00:27:c8:48:62 brd ff:ff:ff:ff:ff:ff inet 192.168.0.101/24 brd 192.168.0.255 scope global enp0s3 valid_lft forever preferred_lft forever inet 192.168.0.100/24 brd 192.168.0.255 scope global secondary enp0s3 valid_lft forever preferred_lft forever inet6 fe80::a00:27ff:fec8:4862/64 scope link valid_lft forever preferred_lft forever
Add an Additional IP Address Temporarily
You can also add an additional IP address temporarily to your server easily with ip addr command.
For example, add the IP address 192.168.0.100 temporarily with the following command:
ip addr add 192.168.0.100/24 dev enp0s3 label enp0s3:1
Now, check your IP address with the following command:
ip addr
You should see that the new IP address 192.168.0.100 is assigned to the interface enps3:1.
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: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 08:00:27:c8:48:62 brd ff:ff:ff:ff:ff:ff inet 192.168.0.101/24 brd 192.168.0.255 scope global enp0s3 valid_lft forever preferred_lft forever inet 192.168.0.100/24 scope global secondary enp0s3:1 valid_lft forever preferred_lft forever inet6 fe80::a00:27ff:fec8:4862/64 scope link valid_lft forever preferred_lft forever
Conclusion
Congratulations! You have successfully configured multiple IP addresses on a single network interface. I hope you have now enough knowledge to add multiple IP addresses to your system as per your requirements. If you’re ready to get started configuring multiple IPs on a VPS, check out Atlantic.Net’s VPS Hosting options.
