Nmap Verbose, Debug, and Miscellaneous Flags

Nmap is usually quiet when it performs a scan, so we don’t really know what’s going on behind the scenes. This can become annoying when running a detailed scan and the connection drops halfway. Let’s see how to get more information from Nmap when performing a scan.

Verbose mode

Nmap provides the verbose flag -v to help us know what Nmap is doing during a scan. We can find the scan initiated, ports discovered, and other information at every step of the scan. Let’s run our default scan with the verbose mode.

Here’s a sample result of a scan with verbose mode:

We can see that Nmap lets us know each port it discovers. Usually, Nmap gives the final result with the open/closed port. Using the verbose mode will also give us detailed information about individual ports and protocols being scanned. We can even get detailed info when performing an OS scan or a version scan in verbose mode.

Debug mode

What if we need even more information? Developers and researchers would love to know every single detail happening behind the scenes. Nmap provides a debug mode -d that gives us even more detailed information on every single port being scanned.

There is also a double debug flag -dd that tells us information about the failed ports. However, we’ll rarely use these flags. The debug information is usually complicated and is used by advanced users and security researchers. ...