Linux Networking: Add VLAN on Ubuntu with netplan

VLAN Usage

A VLAN (Virtual Local Area Network) is a logical subdivision of a physical network that allows devices on different physical LANs to communicate as if they were on the same physical LAN. This segmentation helps to manage traffic efficiently, enhance security, and improve network performance by reducing broadcast domains.

Configuration on Ubuntu

Configuration file is located under the folder: /etc/netplan

# List files in the folder
ls /etc/netplan

# Edit the file
sudo nano 00-installer-config.yaml

Content of the file:

# This file is generated from information provided by the datasource.  Changes
# to it will not persist across an instance reboot.  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:
    ethernets:
        eth0:
            dhcp4: true
            optional: true

# Add VLAN 30 with IP Adress
    vlans:
        eth0.30:
            id: 30
            link: eth0
            addresses: [10.3.3.10/24]

    version: 2

Explanation

In this configuration we added VLAN 30 on the eth0 interfaces.

• eth0.30: Represents a VLAN with ID 30 created on the eth0 interface.
• id: 30: The VLAN ID, a unique identifier for this VLAN.
• link: eth0: Indicates that this VLAN is tied to the eth0 physical interface.
• addresses: [10.3.3.10/24]: Assigns a static IP address (10.3.3.10) with a subnet mask (/24) to the VLAN.

Test and Apply configuration

# Try the configuration before applying
netplan try -timeout 120 

# Apply network configuration
netplan apply

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