How to Locate Open Ports in Linux

Reading Time: 9 minutes
openports

What is a Port? 

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.

Wikipedia.com

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).

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Basic Bash Shell Commands – A CLI Tutorial

Reading Time: 14 minutes

What is Bash?

Bash, or the Bourne Again SHell, is based on the Bourne shell. It is the default shell command language interpreter for GNU Linux/Unix and is accessed via a terminal. The shell was the original method for interacting with the operating system before GUIs were implemented. It has the ability to execute single commands, understand regular expressions, as well as scripts written in the bash language. It is currently the default interactive shell on most all modern Linux distributions.

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How to Install and Use ApacheTop

Reading Time: 4 minutes

What is ApacheTop?

ApacheTop is an uncomplicated command line (CLI) utility that is used to monitor http traffic in real-time. It achieves this task by analyzing the incoming apache logs and based on that data presents understandable output to our screen. It can be configured to output X number of hits, or output X number of hits within X seconds.

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How to Install and Use Git-Secret

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What is Git-Secret?

Git-secret is a bash tool that is used to store your private files and information inside of a git repo on your server. The git-secret tool allows us to encrypt sensitive files that are stored inside a secure, encrypted repository. In this article, we will be examining the process of installing and working with git-secret on an 18.04 Ubuntu Server.

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How to Configure Apache Virtual Hosts on CentOS 7

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Today, we will be reviewing how to configure Apache virtual hosts on a CentOS 7 VPS server or Dedicated server. If you host websites, chances are you are hosting more than one. If so, knowing how and why these virtual hosts work should allow you to better understand why they are needed. By default, Apache can host only one document root for all requests, which likely isn’t what you want to happen.

We can use VirtualHost blocks to translate named domains into their appropriate document roots, with new settings per-block as needed. But, what goes into a valid VirtualHost? Where should it be stored?

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How to Update Bash on Fedora 20 and Fedora 21

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Note:
Please note that this article is considered legacy documentation because Fedora 20 and 21 has reached its end-of-life support.
Pre-Flight Check
  • These instructions are intended specifically for updating Bash on Fedora 20 and Fedora 21.
  • I’ll be working from both a Liquid Web Self Managed Fedora 20 server and a Liquid Web Self Managed Fedora 21 server, and I’ll be logged in as root.
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CVE-2014-6271 and CVE-2014-7169 Info – Bash Vulnerabilities

Reading Time: 2 minutesOn September 24th, a vulnerability was reported in the GNU Bourne-Again-Shell (BASh, or Bash), specifically a flaw with how Bash processes values of environment variables, that allows remote code execution of varying types in many common configurations. The overall risk is severe due to bash being configured for use, by default, on most Linux servers. While Liquid Web immediately began working to proactively patch this vulnerability, some servers may remain vulnerable depending on their update settings or other unforeseen intervening factors. Thus, we’ve provided the instruction below. To Summarize:
  • This flaw exploits Bash, a Unix command-line shell run by default on most Linux servers.
  • Allows for remote code execution, and many types of command-line based attacks.
  • A patch is available, and your server can be easily updated.
  • We have tutorials on How to Update Bash on Red Hat and CentOS and How to Update Bash on Debian and Ubuntu.
  • Test the vulnerability of your server with the information below.
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How to Update Bash on Red Hat and CentOS

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Pre-Flight Check
  • These instructions are intended specifically for updating Bash on Red Hat and CentOS.
  • I’ll be working from both a Liquid Web Core Managed CentOS 6 server and a Liquid Web Self Managed CentOS 7 server, and I’ll be logged in as root.
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How to Update Bash on Debian and Ubuntu

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Pre-Flight Check
  • These instructions are intended specifically for updating Bash on Debian and Ubuntu.
  • I’ll be working from both a Liquid Web Core Managed Ubuntu 14.04 server and a Liquid Web Self Managed Debian 7.4 server, and I’ll be logged in as root.
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How to Update Bash on CentOS 6 and CentOS 7

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Pre-Flight Check
  • These instructions are intended specifically for updating Bash on CentOS 6 and CentOS 7.
  • I’ll be working from both a Liquid Web Core Managed CentOS 6 server and a Liquid Web Self Managed CentOS 7 server, and I’ll be logged in as root.
Continue reading “How to Update Bash on CentOS 6 and CentOS 7”