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.

• [NSE] Made numerous improvements to ssl-heartbleed to provide more reliable detection of the vulnerability.
• [Zenmap] Fixed a bug which caused this crash message: IOError: [Errno socket error] [Errno 10060] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.The bug was caused by us adding a DOCTYPE definition to Nmap's XML output which caused Python's XML parser to try and fetch the DTD every time it parses an XML file.  We now override that DTD-fetching behavior.
• [NSE] Fix some bugs which could cause snmp-ios-config and snmp-sysdescr scripts to crash
• [NSE] Improved performance of citrixlua library when handling large XML responses containing application lists.