NMAP

NMAP, or Network Mapper, is a powerful network scanning tool used to discover hosts and services on a computer network. It sends specially crafted packets to the target and analyzes the responses to determine what services are running, what operating systems are in use, and other network characteristics. NMAP is widely used by network administrators for network inventory, managing service upgrade schedules, and monitoring host or service uptime.

What is NMAP

NMAP, short for Network Mapper, is an open-source network scanning tool that is widely used for network discovery and security auditing. It was created by Gordon Lyon, also known by his pseudonym Fyodor Vaskovich, and has been in active development since its release in 1997. NMAP is capable of scanning large networks efficiently, making it a favorite among network administrators and security professionals.

The tool works by sending specially crafted packets to the target hosts and analyzing the responses. This allows NMAP to determine a variety of information about the target, including which ports are open, what services are running on those ports, the operating system of the target, and even the presence of certain security features like firewalls.

NMAP supports a wide range of scanning techniques, from simple ping scans to more complex SYN scans, and can be used to identify vulnerabilities in the network. It also includes a scripting engine that allows users to write custom scripts for more advanced scanning and detection tasks. NMAP is an essential tool for network management, security auditing, and vulnerability assessment.

NMAP runs on TCP and UDP port 689 and is official IANA port.

Security risk

If port 689 is open and NMAP is running, it could expose the network to unauthorized scanning and potential exploitation. Attackers could use NMAP to gather information about the network, identify vulnerabilities, and plan further attacks. It is crucial to secure this port and monitor for any unauthorized access to mitigate these risks.

In our UFW tutorial you can follow instructions how you can configure UFW to close port 689. Use StackChanges to monitor if the NMAP port is closed and stays closed. StackChanges will send an alert if port 689 is open again.