Installing loopback interfaces in Ubuntu

Note: Run all commands as root

apt-get install uml-utilities
modprobe tun


Running this command will install tap0, tap1 and so on..


tunctl 

To configure the loopback ip address/mask:

for tap0:
ifconfig tap0 (ip-address) netmask (mask) up

to test run ifconfig

To remove the configured ip addresses:

ip addr flush tap0


To remove the loopback interfaces:

tunctl -d tap#