How can I clear (flush) my DNS cache in Linux?

The Domain Name System (DNS) translates user-friendly domain names into the numerical IP addresses that computers understand. This translation process is expedited by the DNS cache, a local repository storing recent domain name lookups. While this cache enhances online efficiency, there are instances when its clearance becomes necessary. So, today, we will explain what it is and how to flush it in Linux systems and guide you through the process.

What is DNS Cache?

The Domain Name System (DNS) is a fundamental component of the internet, responsible for translating human-readable domain names into IP addresses that computers use to locate and communicate with each other. To expedite this process and reduce the time it takes to access websites or other online resources, operating systems and web browsers often maintain a local DNS cache.

In simple terms, a DNS cache stores recent DNS lookups, including the corresponding IP addresses. This means that when you visit a website, your computer doesn’t need to perform a full DNS lookup every time, which can improve page loading times. Instead, it can quickly retrieve the IP address from the cache. However, there are times when you might want to clear or flush it.

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​Linux, the object of the DNS cache poisoning attack

In 2020, researchers from the University of California and Tsinghua University found a new method to execute DNS cache poisoning attacks. Unfortunately, Linux, a very reliable OS, was the object of the DNS cache poisoning attack.

What is DNS cache poisoning?

A DNS cache poisoning (DNS spoofing) is a cyberattack that pollutes the cache on DNS resolver servers. This can cause the user to be redirected to the attacker’s server instead of the right one.

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How to use the Traceroute command?

Are you a network administrator and want to gain insight into your network’s traffic? Then, the Traceroute command is here to your rescue! This simple yet powerful network diagnosis tool measures the latency of a connection to a given destination and provides a complete route path and associated latency. In this blog post, we’ll deeply dive into the Traceroute command and discuss how to use it, why to use it, and its benefits. So let’s get started and learn more about this invaluable networking tool!

What is the Traceroute command?

The Traceroute command is a powerful network diagnostic tool used to measure a connection’s latency to a given destination. When executed, this command sends a series of ICMP packets to the target, each with an increasing TTL value. As the responses are returned from each hop in the route to the destination, the Traceroute command can display the route path and associated latency. It can help network administrators find latency issues, track down errors, and understand the route path between two points. It is a valuable tool for troubleshooting and understanding networks.

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​How to check DNS records on Windows, Linux and macOS?

Being an online business owner or a network administrator, checking DNS records will become a constant task for you. So better to know how to do it from now!

How to check DNS records on Windows, Linux and macOS? 

To check DNS records on Windows, Linux, and macOS, you can use the nslookup command. This command allows you to query DNS servers for information about a specific domain or hostname. Linux and macOS have another choice to check DNS records which is the host command. Both “nslookup” and “host” work well, but the second provides more detailed statistics and more options for precise searches. We do recommend using the host command!

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​What is the Ping command, and how does it work?

It seems that Ping was originally a sonar term to mean an audible wave of sound sent out to find an object. When the sound certainly hits an object, this encounter will produce sound waves whose reflection or echo will get back to its original source. This return of the sound wave can be measured in terms of time and direction. Then, distance and the object’s location can be defined.

Now, let’s jump from the ocean to computing and networking.

What is the Ping command?

The Ping command is a command line utility you can find pretty much in any operating system (OS) with network connectivity. A command line utility is a line of only text that can be entered on the command line of a computer to give it instructions for executing specific tasks.

How to use the Ping command?

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​Host command explained in detail

Knowing the Host command in detail is very useful. It is a Domain Name System (DNS) checking tool that can greatly help you. From now, consider time reading this article a good investment.

What is the Host command?

Host command is a helpful network utility to diagnose and check DNS records. Technically, it is software, and through its command-line interface, you can test the types and specific DNS records you want.

Linux Host command – Options & Examples

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Dig command: How to use it in Linux?

What does the Dig command do?

Domain Information Groper, or DIG for short, is a wonderful command-line utility. To provide comprehensive details on mail exchanges, host addresses, and other relevant information, we use Dig to query the DNS name server. This utility is compatible with a variety of operating systems, including Linux and macOS.

You can do DNS queries using the built-in Linux Dig command by using the Terminal application. Your domain can be troubleshot, and you can learn a lot of details about it, such as DNS records, Name servers, and general network information. Its excellent features include having more functionality than some built-in utilities, like nslookup, and being quite simple to use. Because of this, despite having a straightforward command-line interface, many network administrators use it often.

The most popular examples of the Dig command!

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Popular Linux commands every beginner should know

Linux commands – Explanation

Linux commands are Linux operating system utilities. An interface that receives lines of text and converts them into instructions for your computer is known as a command line.

In addition, we use the Linux terminal to run the commands. Similar to the command prompt in the Windows OS, the terminal is a command-line interface for interacting with the system. A graphical user interface (GUI) is simply a command-line application abstraction. 

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An Introduction to Linux Basics

A brief history of Linux Basics

A sizable group of enthusiasts worked on the Linux Basics Operating System online. A Finnish university student named Linus Torvalds began work on the project in 1990, initially seeing the development of an Operating System as a homework assignment. Since then, it has significantly expanded and evolved into the most feature-rich Unix clone that can execute applications, much like the avalanche of Linux.

Linux is a potent, quick, and free piece of software that is becoming more and more well-liked online.

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