How To Setup and Save VLANs on Ethernet in Ubuntu

In this article, we will walk you through the process of setting up and saving VLANs (Virtual Local Area Networks) on an Ethernet network card in Ubuntu. VLANs are a powerful tool for segmenting networks into smaller, more manageable parts.

Prerequisites

Before we start, ensure that you have administrative access to your Ubuntu system. You will need to execute some commands with superuser privileges.

Step 1: Install the VLAN Package

Firstly, we need to install the vlan package. This package provides us with the necessary tools to create and manage VLANs in Ubuntu. You can install it by running the following command:

sudo apt-get install vlan

The sudo command is used to execute the command with superuser privileges. apt-get install vlan is the command that installs the vlan package.

Step 2: Load the 8021q Kernel Module

After installing the vlan package, we need to load the 8021q kernel module. This module is responsible for VLAN tagging in the Linux kernel. Run the following command to load it:

sudo modprobe 8021q

The modprobe command is used to add a module to the Linux kernel. In this case, we’re adding the 8021q module.

Step 3: Create a New VLAN Interface

Now, we can create a new VLAN interface. We will use the vconfig command for this. For example, to create a VLAN interface with ID 100 on eth0, run:

sudo vconfig add eth0 100

Here, vconfig add eth0 100 is the command that adds a new VLAN with ID 100 to the eth0 interface.

Step 4: Assign an IP Address to the VLAN Interface

Once the VLAN interface is created, we need to assign an IP address to it. We can use the ip command for this. For instance, to assign the IP address 10.0.0.1/24 to eth0.100, run:

sudo ip addr add 10.0.0.1/24 dev eth0.100

The ip addr add command is used to assign an IP address to a network interface. 10.0.0.1/24 is the IP address and subnet mask, and dev eth0.100 specifies the network interface.

Step 5: Make the VLAN Setup Permanent

To make the VLAN setup permanent, we need to add the 8021q module to the kernel on boot. Run the following command to achieve this:

sudo bash -c 'echo "8021q" >> /etc/modules'

This command appends the string “8021q” to the /etc/modules file. This file contains the names of kernel modules that should be loaded at boot time.

Step 6: Configure the Interface for System Boot

Next, we need to configure the interface to be available during system boot. Open the /etc/network/interfaces file with a text editor and add the following lines:

auto eth0.100
iface eth0.100 inet dhcp
 vlan-raw-device eth0

Here, auto eth0.100 ensures the interface is brought up at boot time. iface eth0.100 inet dhcp configures the interface to use DHCP to obtain an IP address. vlan-raw-device eth0 specifies the physical device the VLAN interface is attached to.

Conclusion

By following these steps, you should now have a working VLAN setup on your Ubuntu system. Remember to replace eth0 and 100 with your network interface name and desired VLAN ID, respectively. For more information on VLANs and their usage, you can refer to the Ubuntu Server Guide.

Remember, the proper configuration and management of VLANs can greatly enhance the security and performance of your network. Always plan your network layout carefully and test your configurations thoroughly.