How to make port number 80 appear in nmap scan?

Question

When I perform an nmap scan on my localhost why doesn't the port number 80 show up as open even though my browser is open, ssh and telnet ports show up though. If there is a rule or a firewall blocking it then how do I temporarily suspend it. I use Ubuntu 14.10.

Answer 1

Port 80 should only appear in a scan if you have a web server running on your local machine, listening on port 80. Port 80 is the server port, not the client port.

Answer 2

Firstly you can use "netstat -nltp" to check whether you have listened on port 80. Then type command "nmap -P0 -p80 localhost", port number 80 will be showed as open status.