First, let’s define what a port is. According to the IEFT, a port is:
“A logical entity for Internet communication. Ports serve two main purposes: 1. They provide a demultiplexing identifier to separate transport sessions between the same pair of endpoints 2. They may also identify the application protocol and associated service to which processes connect.”
In plain English, this simply means that a port is an endpoint through which data flows back and forth between two computers over a network. A computer has 65535 ports available to share information. These port numbers are based on a 16-bit number, which is where we derive the total number of available ports (0 to 65535).
INXI is one of the best tools that offer a straightforward and comprehensive method for obtaining a wealth of information about a server with a single command.
There are a myriad of individual tools and commands that can be utilized to glean this information from a Linux system. Understanding the specific hardware that underlies a Linux server is an integral part of understanding that server’s capabilities. In this tutorial, we will cover the installation of INXI on an Ubuntu 18.04 server. It will also include some basic command-line usage of the INXI tool.
The command ls stands for list directory contents. And, cleverly, it will do just that: list a directory’s contents! Using it with -F will give a list of the directories contents, and denote items that are other directories with a trailing /.
On my server returns:
allthethings.txt important.doc Indominus/ Misc/ probs.xls Red Wings/ Spreadsheets/ Work/
In the above case, allthethings.txt, garbage.file, important.doc, and probs.xls are files, and Indominus, Misc, Red Wings, Spreadsheets, and Work, each with the trailing /, are directories!
There are many other options, or switches, such as -F that can be used with ls for improved results. For example: