Editing file /etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
address w.x.y.z
netmask 255.255.255.248
gateway w.x.y.u
dns-nameservers a.b.c.d
metric 1
post-up iptables-restore < /etc/iptables.up.rules

#Secondary network interface
auto eth1
iface eth1 inet static
address 10.1.5.1
netmask 255.255.255.0
network 10.1.5.0
broadcast 10.1.5.255
metric 2