Patrick Sanders

VLAN Tagging in Debian

Introduction

Patrick Sanders

Patrick Sanders


linux

VLAN Tagging in Debian

Posted by Patrick Sanders on .
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linux

VLAN Tagging in Debian

Posted by Patrick Sanders on .

I run a Debian box at work with a Windows VM for some less-avoidable tasks. Due to some network restructuring, we now need to have our host and guest OSes in separate VLANs. This post briefly explains the process of accomplishing this task.

Keep in mind that your switch port will need to be trunked for this to work at all. I am by no means a network guy, so the network side of things is outside the scope of this post.

Enable 802.1q

802.1Q is "the networking standard that supports Virtual LANs (VLANs) on an Ethernet network" (Wikipedia). We need to load the 802.1Q kernel module to enable VLAN tagging.

In a terminal window, run the following command:

modprobe 8021q  

This will immediately load the 802.1Q kernel module. To be sure the module loads on startup, open etc/modules in a text editor and add this line:

8021q  

Install VLAN package

This is a package that allows you to add VLAN devices to your physical devices.

apt-get install vlan

Configure network interfaces

This part can be easily be modified to fit your needs. I don't need my host OS to be able to access the same VLAN as my VM, so I don't have an IP assigned to the eth0.10 interface.

Open /etc/network/interfaces and use this configuration, modified for your network:

# The loopback network interface
auto lo  
iface lo inet loopback

# Physical adapter
auto eth0  
iface eth0 inet manual  
  up ifconfig eth0 0.0.0.0 up

# VLAN 10 interface for VMs; no IP
auto eth0.10  
iface eth0.10 inet manual  
  up ifconfig eth0.10 0.0.0.0 up

# VLAN 20 interface for host
auto eth0.20  
iface eth0.20 inet static  
  address *.*.*.*
  netmask 255.255.255.0
  gateway *.*.*.*

Restart network interfaces

ifdown eth0  
ifup eth0  
ifup eth0.10  
ifup eth0.20  

You can now set your VMs to use the eth0.10 interface. If all goes well, you should be able to access VLAN 10 from your VM and VLAN 20 from your host.

Reference: https://wiki.debian.org/NetworkConfiguration

Patrick Sanders

Patrick Sanders

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