Instalando a o pacote vlan:

# apt-get install vlan

Exemplo de configuração (/etc/network/interfaces):

# The loopback network interface
auto lo
iface lo inet loopback
 
# eth0 -> Interface em acesso (VLAN 50)
# eth1 -> Interface em tronco
 
# The primary network interface
auto eth0
iface eth0 inet static
        address 10.50.0.25/16
#       gateway 10.50.0.1
        dns-nameservers 146.164.170.11 146.164.150.11
        dns-search tic.ufrj.br
 
auto vlan51
iface vlan51 inet static
        address 146.164.51.25/24
        gateway 146.164.51.1
        dns-nameservers 146.164.170.11 146.164.150.11
        dns-search tic.ufrj.br
        vlan_raw_device eth1
        mtu 1500
 
auto vlan52
iface vlan52 inet static
        address 10.52.0.25/24
#       gateway 10.52.0.1
        dns-nameservers 146.164.170.11 146.164.150.11
        dns-search tic.ufrj.br
        vlan_raw_device eth1
        mtu 1500