Target doesn’t respond at all, probably due to a firewall dropping all incoming packets in which case the port will be considered filtered.

The target responds with an RST packet that signifies that the port is closed.

In this type of scan, Nmap sends a TCP packet to a port with the SYN flag set. Nmap supports a lot of different scan types.

nmap -p- 127.0.0.1: This scans all the ports on the localhost.

nmap -p 1-100 127.0.0.1: This scans ports from 1 to 100 on localhost.

nmap -p 80 127.0.0.0.1: This scans port 80 on localhost.

It can be a single port as well as a range of ports. Presently this enables OS detection (-O), version scanning (-sV), script scanning (-sC) and traceroute (–traceroute) Deprecated format as users are now moving towards XML outputs.

-oG: Produce “grepable” output and store it to a file.

-oX: Produce output in a clean, XML format and store it in a given file.

-oN: Redirect normal output to a given filename.

However you can specify the format of your choice with :

-oA: Same Nmap output in “normal”, XML and grepable formats.

You can always specify the verbosity level by specifying a number like this. The minimum level of verbosity advised for use.

You can even set the verbosity level as such :

-sV: Probe open ports to determine service/version info.

Nmap is strong and powerful networking scanning to tool which allows for customizing our scans with the help of flags passed via the command line. Note that you may also need to run it with sudo privileges at times to perform some particular types of scans, Nmap Switches

What is zenmap typically used for