A virtual LAN is any broadcast domain that is partitioned and isolated in a computer network at the data link layer. LAN is an abbreviation of local area network. Short for virtual LAN, a VLAN is a network of computers that behave as if they are connected to the same wire even though they may actually be physically located on different segments of a LAN. VLANs are configured through software rather than hardware, which makes them extremely flexible. One of the biggest advantages of VLANs is that when a computer is physically moved to another location, it can stay on the same VLAN without any hardware reconfiguration.
HOWTO: Set Using The Command Line
sudo apt-get install vlan sudo vconfig add eth0 1 sudo ifconfig eth0.1 192.168.1.100 netmask 255.255.255.0 broadcast 192.168.1.255 up sudo ifconfig eth0.1