How to Assign a Subnet on Ubuntu 20.04, 22.04 & 24.04

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While all servers are deployed with a Management IP address by default, which provides a fixed address for each server, assigning a public IP subnet to a server allows for multiple IP addresses to be used on the same server, with specific IPs reserved for essential network functions. Please note that presently subnet services are only available for dedicated bare metal servers.

This guide will explain how to set up and assign a public IP subnet to dedicated servers running Ubuntu, version 20.04, 22.04, and 2404 using "netplan". After applying changes, the network service will restart, which may temporarily disconnect active connections. Incorrect configuration can therefore result in losing remote access to the server. It’s recommended to keep a backup of the original configuration file before beginning the process.

#Instructions to Assign a Public IP Subnet on Ubuntu

#Step 1: Access the Client Portal

Log in to your client portal.
Click on the "Network" button at the top of the menu bar.

#Step 2: Verify Your Subnet Allocation and Assign IP Addresses

In the "Network" section of the client portal, navigate to the "Subnets" tab to view all available subnets.
You will now see a list of all available subnets. Locate the subnet you wish to configure.
To assign individual IP addresses from the subnet, click on the subnet in the list. This will display all available IP addresses within that subnet.
Once you've identified the IP address you want to assign to your server, click the "Attach +" button next to that IP address. This action lets you associate the selected IP address with your server.

#Step 3: Configure the Subnet on Your Ubuntu Server

Access the server via SSH.

If you are unsure how to connect to your server, please visit our dedicated guide on how to connect to a Linux server using SSH.

Edit the "netplan" configuration.

Open the "netplan" configuration file using the following command:

sudo nano /etc/netplan/50-cloud-init.yaml

Update the configuration to include your subnet IPs under “bonds” as shown below:

OutputGNU nano 7.2

network:
  version: 2
  ethernets:
    enp65s0f0:
      match:
        macaddress: "ac:1f:6b:3a:ca:7a"
      set-name: "enp65s0f0"
      mtu: 1500

    enp65s0f1:
      match:
        macaddress: "ac:1f:6b:3a:ca:7b"
      set-name: "enp65s0f1"
      mtu: 1500

    enp65s0f2:
      match:
        macaddress: "ac:1f:6b:3a:ca:7c"
      optional: true
      set-name: "enp65s0f2"
      mtu: 1500

    enp65s0f3:
      match:
        macaddress: "ac:1f:6b:3a:ca:7d"
      optional: true
      set-name: "enp65s0f3"
      mtu: 1500

  bonds:
    bond0:
      addresses:
        - "93.115.25.17/25"   # Primary IP of the server
        - "46.166.164.250/29" # First IP from the subnet
        - "46.166.164.251/29"
        - "46.166.164.252/29"
        - "46.166.164.253/29"
        - "46.166.164.254/29" # Last IP from the subnet

      nameservers:
        addresses:
          - 46.166.166.46
          - 5.199.160.160
        search:
          - maas

      gateway4: 93.115.25.1
      macaddress: "ac:1f:6b:3a:ca:7a"
      mtu: 1500
      interfaces:
        - enp65s0f1
        - enp65s0f0
      parameters:
        mode: "802.3ad"
        mii-monitor-interval: "100"
        up-delay: "0"
        down-delay: "0"
        lacp-rate: "slo

Save the file and exit (CTRL+X, then Y, and ENTER)

Apply the new configuration by running:
Command Line
```
sudo netplan apply
```

Verify the changes.

Check if the new subnet has been successfully assigned by running the “ip a” command:

ip a

You should see the new IP assignment under “bond0”, like in the example below:

Outputroot@content-kit:~# ip a
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 no_prefixroute
       valid_lft forever preferred_lft forever

2: enp65s0f0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc mq master bond0 state UP group default qlen 1000
    link/ether ac:1f:6b:3a:ca:7a brd ff:ff:ff:ff:ff:ff

3: enp65s0f1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc mq master bond0 state UP group default qlen 1000
    link/ether ac:1f:6b:3a:ca:7b brd ff:ff:ff:ff:ff:ff permaddr ac:1f:6b:3a:ca:7b

4: enp65s0f2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether ac:1f:6b:3a:ca:7c brd ff:ff:ff:ff:ff:ff

5: enp65s0f3: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether ac:1f:6b:3a:ca:7d brd ff:ff:ff:ff:ff:ff

6: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether ac:1f:6b:3a:ca:7a brd ff:ff:ff:ff:ff:ff
    inet 93.115.25.17/25 brd 93.115.25.127 scope global bond0
       valid_lft forever preferred_lft forever
    inet 46.166.164.250/29 brd 46.166.164.255 scope global bond0
       valid_lft forever preferred_lft forever
    inet 46.166.164.251/29 brd 46.166.164.255 scope global secondary bond0
       valid_lft forever preferred_lft forever
    inet 46.166.164.252/29 brd 46.166.164.255 scope global secondary bond0
       valid_lft forever preferred_lft forever
    inet 46.166.164.253/29 brd 46.166.164.255 scope global secondary bond0
       valid_lft forever preferred_lft forever
    inet 46.166.164.254/29 brd 46.166.164.255 scope global secondary bond0
       valid_lft forever preferred_lft forever
    inet6 fe80::aef1:6bff:fe3a:ca7a/64 scope link
       valid_lft forever preferred_lft forever

7: bond0.2516@bond0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether ac:1f:6b:3a:ca:7a brd ff:ff:ff:ff:ff:ff
    inet 10.175.52.28/24 brd 10.175.52.255 scope global bond0.2516
       valid_lft forever preferred_lft forever
    inet6 fe80::aef1:6bff:fe3a:ca7a/64 scope link
       valid_lft forever preferred_lft forever

Test connectivity.

Ping the new IP addresses from the subnet to test the connection by running the following command and replacing “” with one of the IPs from the subnet.
Command Line
```
ping -c 5 <new-ip-address>
```
A successful response indicates that the IP addresses has been correctly configured.

#Step 4: Ensure The Configuration Persists Through Reboots

To ensure that your changes stick after a reboot you must turn off Cloud-init's network configuration.

To do this, Create the persistence configuration file and add the configuration with:
Command Line
```
echo "network: {config: disabled}" | sudo tee /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg 
```

This setup enables and configures multiple IP addresses for different services on a single server, enhancing scalability and flexibility for your network configuration.

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