Bind multiple ip address to NIC in Debian

First, back up your working interface to somewhere.

# cp /etc/network/interfaces /root/bak.interface

Then edit file

# vi /etc/network/interfaces

## This is how to bind multiple ip to NIC

auto eth0

auto eth0:0

auto eth0:1

iface eth0 inet static

address 192.168.20.31

netmask 255.255.255.0

gateway 192.168.20.1

iface eth0:0 inet static

address 192.168.20.32

netmask 255.255.255.0

gateway 192.168.20.1

iface eth0:1 inet static

address 192.168.20.33

netmask 255.255.255.0

gateway 192.168.20.1

##save and quit

##restart network service