It was designed to rapidly scan large networks.

nmap: Nmap (“Network Mapper”) is an open source tool for network exploration and security auditing.

nc: Netcat is a simple Unix utility which reads and writes data across network connections, using TCP or UDP protocol.

In this article, we will show you, how to check if a network port is opened or closed on a remote Linux system using the below three methods.

Please note: You also need to open these network ports in the hardware firewall against your server IP, if you already managing it. If the application port is not open, it will make the program throw errors and hence malfunction.įor instance, when you configure the Apache Web server on Linux, you must open ports 80 and 443 that listens to incoming connections for Apache on the firewall, and that allows users to access websites hosted on your web server through the browser.

When installing or configuring an application in the Linux system, the associated port should also be open which allows the application for external access.

PortScan & Stuff 1.95 download