closing port with ease on Linux

use nmap utility to close the port .

run this command

bash#nmap localhost

the output will be like

Interesting ports on localhost (127.0.0.1)
Not shown: 1711 closed ports

PORT STATE SERVICE
25/tcp open smtp
80/tcp open http

Now if you want to close port 80 , simply run this

bash#fuser -k 80/tcp 


you can also use ipaddress instead of localhost while using nmap command