Nmap is a well-known and widely used networking tool in information security. CompTIA’s PenTest+ exam tests users for their Nmap knowledge. You must also know the meaning of flags and how to use them if you want Nmap to be understood.
Nmap flags can simply be described as the parameters Nmap uses in order to achieve certain objectives. It’s not easy to know how to use them. There are many Nmap commands. The parameters or flags will allow you to tell Nmap exactly how you want it to work.
Nmap is a powerful and versatile tool that can be used from any command line, including Windows, Linux and macOS. Nmap is widely used and can be seen on TV and in movies being used by movie hackers. Nmap has been featured in movies such as Oceans 8 and The Bourne Ultimatum. Nmap is well-known by movie consultants.
Let’s take a look at some of these flags, especially if we are going to tackle Pentest+.
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CompTIA PenTest+ Exam Objective 4.0 requires that candidates have Nmap knowledge in order to be successful. Candidates must understand the basic requirements of the exam objective if they want to pass it. These will be reviewed and then we will dive into other Nmap flags.
What can you do with Nmap? Many of Nmap’s features can be seen in its name, which stands for Network Mapper. Nmap is a network discovery tool and security auditing tool. It can detect open ports, running service versions, operating system types and versions, packet routing, host monitoring, and other services. It is a tool that all pentesters should be familiar with.
Command Analysis with Flags
Let’s look at an Nmap command example and then break it down to its basic components. Here’s an example.
nmap –sT –sV Pn p 1-60000T2 —oA scanme.nmap.orgThis is quite a command. Each parameter is a Nmap flag, and each one has a unique purpose. Below is a description of each parameter in the sample command.
The first flag (-sT) invokes a TCP connection scan.
The next flag (-sV) attempts to determine which services are operating on the target.
The third flag (-Pn) disables the command ping and scans ports only.
The fourth flag (-p), 1-65435 runs port scans from port 1 to 60000.
The fifth flag (-T2) informs the command that polite Intrusion Detection Software evasion is to be used to get by unnoticed (hopefully).
The sixth and final flag (oA) is used to specify all output file types. Testscan is the variable that specifies the filename for the output files. The scan will produce 3 files called:
testscan.nmap
testscan.xml
testscan.gmap
The target to be scanned is located at the end of the command. scanme.nmap.org allows you to scan it using Nmap. This is a good example of how Nmap works. There are some exceptions, however, as explained on the page.
“Hello, and welcome at Scanme.Nmap.Org. This service is provided by the Nmap Security Scanner Project, and Insecure.Org.
This machine was set up to assist people in learning about Nmap, and to verify that their Nmap installation (or Internet connectivity) is working properly. This machine can be scanned with Nmap and other port scanners. Do not hammer on the server. You can scan a few times per day, but not 100.
This request should be considered when you test the commands yourself.
5 Nmap Flag Variations: Scanning, Discovery, Ports, Services, Output
Nmap is widely used because it is customizable from scan to scan. You can plan your scans and pinpoint many different points.
