Configuring vlan on ubuntu.

Scenario
Recently while doing the configuration for AWS Direct Connect, I wanted to configure onPrem Ubuntu physical host as a router. Having vlan is one of the pre-requisite and vlan onPrem switch/router should be same as created for virtual interface on AWS console. In this post, I'll explain how I configured vlan on Ubuntu. and I could configure a Ubuntu as a router for AWS Direct Connect.

Installation

#sudo apt-get install vlan 

then Load the 8021q module into the kernel.

#sudo modprobe 8021q

Configuration
Keep in mind, you can create a vlan on physical interface. There should not be any IP address assigned to the physical interface.

ifconfig outout before vlan configuration:

root@ubuntu:/home/ubuntu# ifconfig 
eno1      Link encap:Ethernet  HWaddr 78:2b:cb:20:60:71  
          inet addr:10.10.91.219  Bcast:10.10.255.255  Mask:255.255.0.0
          inet6 addr: fe80::7a2b:cbff:fe20:6071/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5018984 errors:0 dropped:3117 overruns:0 frame:0
          TX packets:108811 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:404946421 (404.9 MB)  TX bytes:25990616 (25.9 MB)

enp5s0f0  Link encap:Ethernet  HWaddr a0:36:9f:20:7d:48  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

enp7s0f0  Link encap:Ethernet  HWaddr 00:1b:21:bf:10:e8  
          inet6 addr: fe80::21b:21ff:febf:10e8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:419179528 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5283119829 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:16904 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16904 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:1324287 (1.3 MB)  TX bytes:1324287 (1.3 MB)

root@ubuntu:/home/ubuntu#


eno1 was used as management interface, and enp7s0f0 is the interface where I wanted to configure vlan 112.

To create vlan run:

# vconfig add enp7s0f0 112 -v
Added VLAN with VID == 112 to IF -:enp7s0f0:-

Now, ifconfig -a should list the new vlan with same HWaddr or you cat vlan config file.

root@ubuntu:/home/ubuntu# cat /proc/net/vlan/config
VLAN Dev name | VLAN ID
Name-Type: VLAN_NAME_TYPE_PLUS_VID_NO_PAD
vlan112        | 112  | enp7s0f0
root@ubuntu:/home/ubuntu# 

Now, you should assign IP to the new interface. You can IP/subnet add in /etc/network/interfaces as follow

root@ubuntu:/home/ubuntu# cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
        iface vlan112 inet static
        vlan-raw-device enp7s0f0
         address x.x.x.x
         netmask 255.255.255.254


root@ubuntu:/home/ubuntu#

and run

#ifup vlan112

To make interface up or assign IP from command line.

or

#sudo ip addr add x.x.x.x/31 dev vlan112

To make this setup permanent, the following lines have to be added.

 Add the module to the kernel on boot:

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

After vlan is up, you should see similar output in ifconfig command.

root@ubuntu:/home/ubuntu# ifconfig 
eno1      Link encap:Ethernet  HWaddr 78:2b:cb:20:60:71  
          inet addr:10.10.91.219  Bcast:10.10.255.255  Mask:255.255.0.0
          inet6 addr: fe80::7a2b:cbff:fe20:6071/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5018984 errors:0 dropped:3117 overruns:0 frame:0
          TX packets:108811 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:404946421 (404.9 MB)  TX bytes:25990616 (25.9 MB)

enp5s0f0  Link encap:Ethernet  HWaddr a0:36:9f:20:7d:48  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

enp7s0f0  Link encap:Ethernet  HWaddr 00:1b:21:bf:10:e8  
          inet6 addr: fe80::21b:21ff:febf:10e8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:419179528 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5283119829 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:36109877661 (36.1 GB)  TX bytes:7772287763609 (7.7 TB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:16904 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16904 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:1324287 (1.3 MB)  TX bytes:1324287 (1.3 MB)

vlan112   Link encap:Ethernet  HWaddr 00:1b:21:bf:10:e8  
          inet addr:x.x.x.x  Bcast:255.255.255.255  Mask:255.255.255.254
          inet6 addr: fe80::21b:21ff:febf:10e8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:414301718 errors:0 dropped:0 overruns:0 frame:0
          TX packets:471054486 errors:0 dropped:1925565 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:29987695023 (29.9 GB)  TX bytes:7504521160847 (7.5 TB)

root@ubuntu:/home/ubuntu#