The ‘-vv’ specifier for nmap is a command line option that stands for verbose mode. Nmap is a free and open source software application for network exploration or security auditing. It is widely used for its capabilities like network inventory, managing service upgrade schedules, and monitoring host or service uptime.
The ‘-vv’ specifier in Nmap is used to increase the verbosity level of the program output, making it much more detailed. It increases the amount of information reported back to the user about the scan details and progress of network mapping. Essentially, it makes nmap report much more about what it is doing, what it’s found and how it’s processing.
You can use nmap -vv to gather information such as IP addresses, the operating system used by the devices on the network, open ports, and running services. For instance, if you are scanning for open ports, nmap -vv will give you a detailed rundown of each port that is scanned, its current state (open/closed), the service running on that port, the version of that service, and other related information.
The ‘-vv’ option is most effective for diagnostic purposes or for advanced users who want to delve into detailed analysis of their networks. For simple tasks or for beginners, it may provide overwhelming information.
It is suggested in the official Nmap documentation to use ‘-vv’ when trying to troubleshoot strange behavior or to get a better understanding of what Nmap is doing behind the scenes (Source: Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning, Gordon Lyon).
An example of its usage, cited from “Nmap Cookbook: The Fat-free Guide to Network Scanning” by Nicholas Marsh, is `nmap -vv -sS 192.168.1.0/24`. This command scans all the hosts on the subnet 192.168.1.0/24 using a Syn scan and will output detailed results because of the ‘-vv’ option.
The ‘-vv’ specifier is one of several options used to alter the verbosity level in Nmap. There is also ‘-v’ for increased verbosity and ‘-v0’ for less verbosity. However, ‘-vv’ provides the highest level of detail which is why it is often used for thorough network examination and problem diagnosis.
Sources:
1. Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning by Gordon Lyon
2. Nmap Cookbook: The Fat-free Guide to Network Scanning by Nicholas Marsh
