nmap Output

Let's look at some way to obtain better output:

• while in the interactive mode, if we are waiting for results we can press "Enter" and get some lines describing what nmap is doing
• if we append the --reason in any case nmap is doing a port scan, we'll notice the reason why nmap determined that the examined ports were closed or opened
• if we are only interested in the open ports, and not even the filtered ones, so we must append --open
• we can output the results in a file with: "-o", we can save results into different formats:
  • N, normal format
  • X, XML format
  • G, grepable format
  • A, all formats

An example of these could be:

nmap -oN fileName.txt

What I personally prefer in scanning activities is:

nmap -oA filename_prefix

Note that saving an output report is extremely useful also in cases where we are scanning large subnets and want to handle nmap crashes or reboots. Indeed, we can restore an interrupted scan from its template by doing:

nmap --resume <logfile_name>