how to configure linux virtual local area network vlan
Method #1: CentOS/RHLE/Fedora Linux VLAN HowTo
I am using RHEL/CentOS Linux with VLAN ID # 5. So I need to copy file /etc/sysconfig/network-scripts/ifcfg-eth0 to /etc/sysconfig/network-scripts/ifcfg-eth0.5
# cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0.5
Now, I've one network card (eth0) and it needs to tagged network traffic for VLAN ID 5.
- eth0 - Your regular network interface
- eth0.5 - Your virtual interface that use untagged frames
Do not modify /etc/sysconfig/network-scripts/ifcfg-eth0 file. Now open file /etc/sysconfig/network-scripts/ifcfg-eth0.5 using a text editor such as vi, type:
# vi /etc/sysconfig/network-scripts/ifcfg-eth0.5
Find DEVICE=eth0 line and replace with:
DEVICE=eth0.5
Also, append the following line:
VLAN=yes
Make sure you assign correct IP address using DHCP or static IP. Remove gateway entry from all other network config files. Only add gateway to /etc/sysconfig/network file. This whole configuration may sound complicated. So I am including sample configurations files for you:
/etc/sysconfig/network-scripts/ifcfg-eth0.5 file
# VLAN configuration for my eth0 with ID - 5 # DEVICE=eth0.5 BOOTPROTO=none ONBOOT=yes IPADDR=192.168.1.5 NETMASK=255.255.255.0 USERCTL=no NETWORK=192.168.1.0 VLAN=yes
/etc/sysconfig/network-scripts/ifcfg-eth0 file
# Actual configuration for my eth0 physical interface ## DEVICE=eth0 TYPE=Ethernet BOOTPROTO=none ONBOOT=yes
Finally, restart networking service on a CentOS/RHEL/Fedora Linux, type:
# /etc/init.d/network restart
OR
# service network restart
NOTE: If you need a second VLAN i.e. you need to configure for VLAN ID 2 then copy the /etc/sysconfig/network-scripts/ifcfg-eth0 to /etc/sysconfig/network-scripts/ifcfg-eth0.2 and do the above procedure again.
Method #2: Using the vconfig command
Above method is perfect and works with a Red hat Enterprise Linux / CentOS / Fedora Linux without any problem. However, you will notice that there is a command called vconfig. The vconfig program allows you to create and remove vlan-devices on a vlan enabled kernel. Vlan-devices are virtual Ethernet devices which represents the virtual lans on the physical lan. This is yet another method of configuring VLAN. To add VLAN ID 5 with following command for eth0 interface:
# vconfig add eth0 5
The vconfig add command creates a vlan-device on eth0 which result into eth0.5 interface. You can use normal ifconfig command to see device information:
# ifconfig eth0.5
Use ifconfig command to assign IP address to vlan interfere:
# ifconfig eth0.5 192.168.1.100 netmask 255.255.255.0 broadcast 192.168.1.255 up
To get detailed information about VLAN interface, type:
# cat /proc/net/vlan/eth0.5
If you wish to delete VLAN interface use delete command as follows:
# ifconfig eth0.5 down
# vconfig rem eth0.5
See vconfig(8) Linux man page for more information on syntax and examples.
Method #3: Create the VLAN device using the ip command
Use the ip command as follows for the interface eth0, and the vlan id is 5:
# ip link add link eth0 name eth0.5 type vlan id 5
# ip link
# ip -d link show eth0.5
You need to activate and add an IP address to vlan link, type:
# ip addr add 192.168.1.200/24 brd 192.168.1.255 dev eth0.5
# ip link set dev eth0.5 up
All traffic will go through the eth0 interface bith with a BLAN tag 5. Only VLAN aware devices can accept the traffic, otherwise the traffic is dropped.
How can I remove VLAN ID 5?
Type the following commands
# ip link set dev eth0.5 down
# ip link delete eth0.5
How do I make above VLAN configuration permanent on a Debian or Ubuntu based system?
Edit the /etc/network/interfaces file, enter:
$ sudo vi /etc/network/interfaces
Update configuration as follows:
## vlan for eth0 with ID - 5 on a Debian/Ubuntu Linux## auto eth0.5 iface eth0.5 inet static address 192.168.1.200 netmask 255.255.255.0 vlan-raw-device eth0
Save and close the file.
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