13.Lock StylizedMotherboard

Learn three methods you can use to check if a network port is opened or closed on a remote Linux system in this tutorial.

When installing or configuring an application in the Linux system, the associated port should also be open which allows the application for external access. If the application port is not open, it will make the program throw errors and hence malfunction.

For 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.