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).
In this article, we will review the Nmap software program and multiple commands. Nmap is an open-source mainstream tool used by network administrators to scan ports and map networks. Nmap commands are primarily used to identify which ports certain software is running on our system. It is also used to discover available hosts and what services they are offering and detecting potential security risks. Using Nmap, you can check a single host or a complete network. In this tutorial, we will cover several basic as well as advanced Nmap commands in the “Pro Tips and Tricks” section of the article.
In this article we will learn what the Network Time protocol (NTP) is and how to install it on the two Linux distributions most commonly used on Liquid Web’s servers. We will be focusing on using CentOS 7 and Ubuntu 18.04 servers, but the process is largely the same on other recent versions of each. Before we start, make sure we are familiar with using SSH (Secure Shell) as we’ll need it to connect to the server. Here’s a link to one of our articles on the basics of SSH if you are unfamiliar with its usage.
Reading Time: 11minutesThe command line terminal, or shell on your Linux server, is a potent tool for deciphering activity on the server, performing operations, or making system changes. But with several thousand executable binaries installed by default, what tools are useful, and how should you use them safely? Continue reading “Useful Command Line for Linux Admins”→