Nmap, short for Network Mapper, is a widely used open-source tool designed for network discovery and security auditing. Developed by Gordon Lyon, Nmap is utilized by network administrators, security professionals, and hackers alike to scan networks and identify hosts and services. It is highly effective for network inventory, managing service upgrade schedules, and monitoring host or service uptime.

Nmap operates by sending specially crafted packets to targeted hosts and analyzing their responses. This process allows it to determine the status of various devices on a network, including which ports are open, which services are running, and which operating systems are in use. Nmap supports a wide range of scanning techniques, including TCP connect, SYN scan, UDP scan, and OS detection, allowing for thorough network analysis.

One of Nmap's key features is its scripting engine (NSE), which enables users to automate tasks such as detecting vulnerabilities, discovering malware, and performing advanced network reconnaissance. NSE scripts are written in Lua, a lightweight programming language, allowing users to extend Nmap’s functionality and customize scans according to their specific needs.

Nmap is supported on multiple platforms, including Windows, macOS, and Linux, making it accessible for users across different operating systems. Its robust features and ease of use make Nmap an essential tool for network security assessments and a fundamental component of many cybersecurity toolkits.

Key Features:

• Host Discovery: Finds live hosts on a network.
• Port Scanning: Scans open ports to see which services are running.
• Service Version Detection: Identifies software versions on open ports.
• OS Detection: Detects the operating system and device type of a host.
• Nmap Scripting Engine (NSE): Uses scripts for tasks like vulnerability detection and automation.
• Firewall Evasion: Bypasses firewalls and security systems during scans.
• Flexible Output: Supports multiple formats for results, like text, XML, and HTML.
• Stealth Scanning: Scans quietly to avoid detection by security systems.
• IPv6 Support: Works with both IPv4 and IPv6 networks.
• GUI (Zenmap): Offers a graphical interface for easier use.

• Integrated all of your IPv4 OS fingerprint submissions since June 2013. Added 366 fingerprints, bringing the new total to 4485. Additions include Linux 3.10 - 3.14, iOS 7, OpenBSD 5.4 - 5.5, FreeBSD 9.2, OS X 10.9, Android 4.3, and more. Many existing fingerprints were improved.
• (Windows, RPMs) Upgraded the included OpenSSL to version 1.0.1i.
• (Windows) Upgraded the included Python to version 2.7.8.
• Removed the External Entity Declaration from the DOCTYPE in Nmap's XML. This was added in 6.45, and resulted in trouble for Nmap XML parsers without network access, as well as increased traffic to Nmap's servers.
• [Ndiff] Fixed the installation process on Windows, which was missing the actual Ndiff Python module since we separated it from the driver script.
• [Ndiff] Fixed the ndiff.bat wrapper in the zipfile Windows distribution, which was giving the error, "\Microsoft was unexpected at this time.
• [Zenmap] Fixed the Zenmap .dmg installer for OS X.
• [Ncat] Fixed SOCKS5 username/password authentication. The password length was being written in the wrong place, so authentication could not succeed.
• Avoid formatting NULL as "%s" when running nmap --iflist. GNU libc converts this to the string "(null)", but it caused segfault on Solaris.
• [Zenmap][Ndiff] Avoid crashing when users have the antiquated PyXML package installed. Python tries to be nice and loads it when we import xml, but it isn't compatible. Instead, we force Python to use the standard library xml module.
• Handle ICMP admin-prohibited messages when doing service version detection.
• [NSE] Fix a bug causing http.head to not honor redirects.
• [Zenmap] Fix a bug in DiffViewer causing this crash: TypeError: GtkTextBuffer.set_text() argument 1 must be string or read-only buffer, not NmapParserSAX Crash happened when trying to compare two scans within Zenmap.