NMAP, or NetworkMapper, is a highly reliable open-source tool used for network discovery and security auditing. This versatile tool allows users to scan a range of ports in order to identify the status of network connections, and can be an invaluable resource for IT professionals. A port range scan with NMAP involves specifying a range of ports that the tool should scan on the target systems. This could be used to find open ports that could serve as possible gateways for cyber-attacks.
Firstly, download and install NMAP from their official website (https://nmap.org/download.html). It supports most operating systems including Windows, Linux, and macOS.
The basic syntax for scanning a port range with NMAP is as follows:
```
nmap -p [port range] [target]
```
- “nmap” is the command that starts the program.
- The “-p” flag is used to specify the port range.
- The [port range] specifies the range of ports that you want to scan. This could be a single port number (e.g., 80), a hyphen-separated range of ports (e.g., 80-443), or a comma-separated list of ports and ranges (e.g., 22,80,443,8000-9000).
- The [target] refers to the IP address or domain name of the system that you want to scan.
For example, if you want to scan all the ports from 1 to 1024 on the system with the IP address 192.168.1.1, you would use the following command:
```
nmap -p 1-1024 192.168.1.1
```
NMAP will then scan the specified range of ports on the target system, providing a report on the status of each port.
It’s critical to note that extensive or aggressive scanning might be interpreted as hostile by the network’s security systems and can even have legal implications, depending on the jurisdiction and the network being scanned. Therefore, never use port scanning tools without explicit permission or on networks where you do not have authority.
For more detailed information on NMAP port scanning techniques, reference could be made to the official NMAP documentation, found at https://nmap.org/book/man-port-scanning-techniques.html. The documentation offers a wealth of information on the subject, revealing strategies that customize scans to suit the user’s specific needs.
Gordon Lyon’s book “Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning” also provides a comprehensive guide to Nmap functionality, including detailed instructions on how to conduct the most accurate and effective port scans.
The book can be accessed online at https://nmap.org/book/toc.html.
References:
1. https://nmap.org/download.html
2. https://nmap.org/book/man-port-scanning-techniques.html
3. https://nmap.org/book/toc.html
