Book Image

Nmap Network Exploration and Security Auditing Cookbook, Third Edition - Third Edition

By : Paulino Calderon
Book Image

Nmap Network Exploration and Security Auditing Cookbook, Third Edition - Third Edition

By: Paulino Calderon

Overview of this book

Nmap is one of the most powerful tools for network discovery and security auditing used by millions of IT professionals, from system administrators to cybersecurity specialists. This third edition of the Nmap: Network Exploration and Security Auditing Cookbook introduces Nmap and its family - Ncat, Ncrack, Ndiff, Zenmap, and the Nmap Scripting Engine (NSE) - and guides you through numerous tasks that are relevant to security engineers in today’s technology ecosystems. The book discusses some of the most common and useful tasks for scanning hosts, networks, applications, mainframes, Unix and Windows environments, and ICS/SCADA systems. Advanced Nmap users can benefit from this book by exploring the hidden functionalities within Nmap and its scripts as well as advanced workflows and configurations to fine-tune their scans. Seasoned users will find new applications and third-party tools that can help them manage scans and even start developing their own NSE scripts. Practical examples featured in a cookbook format make this book perfect for quickly remembering Nmap options, scripts and arguments, and more. By the end of this Nmap book, you will be able to successfully scan numerous hosts, exploit vulnerable areas, and gather valuable information.
Table of Contents (22 chapters)
Appendix A: HTTP, HTTP Pipelining, and Web Crawling Configuration Options
Appendix Β: Brute-Force Password Auditing Options
Appendix F: References and Additional Reading

Using port scanning for host discovery

While port scanning is one of the later phases during a scan, you can only rely on it to determine whether a host is online. For example, if we are scanning a range with only web servers, it can make sense to find hosts running that service using only port scanning. Under the hood, this achieves the same result as an SYN ping scan sent to specific ports.

In this recipe, you will learn how to use only port scanning to determine whether a host is online.

How to do it...

Open your terminal and enter the following command for hosts with port 80 open:

# nmap -Pn -p80 -n <target>

If the service is open, Nmap will mark the host as online. You can use the --packet-trace option to see how host discovery is skipped and only the port discovery process happens:

% nmap -Pn -n -p80 --packet-trace scanme.nmap.org
CONN (0.0357s) TCP localhost > 45.33.32.156:80 => Operation now in progress
CONN (0.1341s) TCP localhost > 45.33.32...