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Month: March 2022

MTR command – A network diagnostic tool for Linux

Many network diagnostic tools are already a part of Linux. For example, Nslookup command, Host command, Dig command, Traceroute command, and more. But, sometime in the past, there was a guy called Matt Kimball. He was just not satisfied with the traceroute command in the 90s, so he decided to make a new one – the MTR command.

What is the MTR command?

The MTR command is a great small tool to trace the route to a target and get information for the round-trip. It is an alternative to the common traceroute command and was written by Matt Kimball created in 1997 to perform functions both from traceroute command and ping command. It provides more information in comparison with the other two commands and is just as easy to use on Linux. Roger Wolff further improved the software in 1998, and the name was changed to My Traceroute. 

On Linux, you can use the MTR command straight through the Terminal application. If you don’t have it installed on your Linux distro, you first need to install it.

On Ubuntu, you can do it by typing: sudo apt update. Then press Enter and write your password. After that, type: sudo apt -y install mtr. Again press Enter.

How does it work?

The MTR command sends ICMP (Internet Control Message Protocol) data packets to the target you set. The target that you decide could be a hostname/domain name or an IP address (IPv4 or IPv6). 

You can use it using the following syntax:

mtr option value target

Mtr – shows which command you are using.

Option – it can use one of the following options to improve your probe further:

-h – help.

-v – version.

-r – report. You need to stop it by pressing the “C” key, and after that, you get a report.

-w – extended report.

-c – number of ICMP messages to be sent.

-s – the size of ICMP data packages.

-t – Curses-based terminal interface.

-n – don’t resolve the hostnames.

-g – GTK+ interface.

-p – split – Split-user interface.

-l – Raw output.

-a – address.

-i – seconds between the ICMP messages.

-u –use UDP.

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What is the purpose of Reverse DNS?

Reverse DNS – What is it?

Reverse DNS, also known as rDNS, is a DNS lookup that maps an IP address to its domain name. It is absolutely the opposite of Forward DNS lookup, where the domain name links to the IP address where it is hosted. 

In the majority of cases, rDNS is an additional service provided by a DNS hosting provider. Once you implement such a service, you should create a Master Reverse zone and add PTR records to it. That way, you are able to provide evidence that your IP address and your domain name have a proper match. 

Thanks to the created PTR record, you actually confirm that the IP address is associated with the domain name. As a result, you are minimizing the chance and avoiding fraud. Additionally, you can implement Reverse DNS both with IPv4 address and A record and with IPv6 address and AAAA record.

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DNS Record Types Cheat Sheet

In case you are just starting managing your DNS, these DNS record types are fundamental. So, let’s explain a little bit more about them.

SOA record

The acronym SOA stands for Start Of Authority, and it is essential to explain this record first. With it, you can show the origin of the authority DNS zone. This DNS record holds inside very important information about the DNS zone. It is a must-have if you want your DNS network to operate normally. The SOA record points to the primary DNS server. In addition, it stores information for the domain administrator and contact information. It also includes parameters such as the domain serial number and how often it should refresh. It is important to note that there should be just one SOA record for a particular DNS zone.

Learn everything about the DNS SOA Record!

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