• Opção 01

# The loopback network interface
auto lo
iface lo inet loopback
 
# The primary network interface 
auto eth0 
allow-hotplug eth0 
iface eth0 inet static
        address 203.0.113.250
        netmask 255.255.255.252
        gateway 203.0.113.249
        dns-domain exemplo.com
        dns-nameservers 8.8.8.8
 
auto eth1
allow-hotplug eth1
iface eth1 inet static
        address 172.16.1.2
        netmask 255.255.255.224
 
post-up route add -net 203.0.113.0/20 gw 172.16.1.1 

• Opção 02

# The primary network interface
allow-hotplug eth0
iface eth0 inet static
        address 192.0.2.250
        netmask 255.255.255.0
        gateway 192.0.2.253
        dns-domain exemplo.com
        dns-nameservers 8.8.8.8
 
## vlan 02
allow-hotplug eth1
iface eth1 inet static
	address 172.20.2.6
	netmask 255.255.255.224
# prefixos 01
        up ip route add 172.16.0.0/17 via 172.20.2.1 dev eth1
        down ip route add 172.16.0.0/17 via 172.20.2.1 dev eth1
# prefixos 02
        up ip route add 172.20.0.0/17 via 172.20.2.1 dev eth1
        down ip route add 172.20.0.0/17 via 172.20.2.1 dev eth1