Category: DNS

DNS CAA record

The DNS CAA record was first defined in 2013, and from September 2017, Certificate Authorities are obliged to review it before issuing any certificate. So, let’s clarify things a little bit more about it.

DNS CAA record – Definition

The CAA (Certification Authority Authorization) record is a Resource Record in DNS (Domain Name System) that lets domain owners to specify which CAs are authorized to issue a certificate for the domain name. 

Certification Authorities (CAs) are organizations that are authorized and able to issue certificates for domain names, for instance, SSL, TLS, or other certificates.

How to create a CAA record?

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DKIM record

DKIM record explained.

Domain Keys Identified Mail for short DKIM record is a DNS record (TXT record) that is utilized to prove that the emails sent from the particular domain name are legitimate via cryptographic authentication.

The recipient, on the other hand, is also going to use the DKIM record when making the DNS query to the domain name for validating the sender. It is going to use the information in the header of the message.

The DKIM record includes the public key, which the recipient needs to confirm the message.

Once you wing an email with DKIM, you are going to attach a DKIM signature header and encrypt it. Then, the server sending the email signs the emails with its private key. After that, the recipients are going to unlock them with the public key. This process ensures that the messages are not going to be spoofed on the route. Additionally, they prove that they can be trusted.

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ALIAS record

We are going to explore one alternative to the CNAME record, which has many advantages – the ALIAS record. With it, you can have different DNS records in the same DNS zone and even put ALIAS records inside the root. Put ALIAS records where you can’t do it with CNAME records and manage your DNS easier. 

ALIAS record

The ALIAS record is one of the DNS record types which serves to connect one hostname to another. After that, it will resolve to A or AAAA record (an A to IPv4 address and an AAAA to IPv6 address) that already exists for the second hostname. ALIAS has the benefit of being allowed for the root domain, and you can put it in a DNS zone with other DNS records like MX records.

Benefits of using ALIAS DNS record

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TTL

Let me tell you a funny story that will show you the importance of TTL when sending packages. 

Back in the day, in 1971, there was a programmer called Bob Thomas who was working on mainframe computers. He got bored and decided to play around. After a while, Bob created a small software called the Creeper and released it on the network. It was a tiny code with the message “I’m the creeper: catch me if you can”. Ray Tomlinson, a colleague of his, added the functionality and allowed the code to copy itself. This was the first computer virus. The virus was unstoppable because there was no antivirus at this time, and it had no TTL, so it could go around the network forever. The co-creator Ray needed to invent the first antivirus to stop it. Otherwise, it could still go around for a long time. 

So what is TTL in networking? 

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IPv4

You will learn what IPv4 is, how an IPv4 address looks like, and what is next after IPv4, IPv6.

What is IPv4?

IPv4 is one, a bit older Internet Protocol that has been around since the early 80s. The 4th version was introduced in 1981 and got in use since 1982. Been an Internet Protocol (IP), its purpose is to establish all the rules for communication. How the data packets should be sent, what should happen with them, how to be received, and so on.

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Ping command

Computer networking has lots of tools. From the most simple to the most complex, all have interesting functionality that sooner or later can be useful for you. 

What’s the Ping command?

Ping command is a software utility for testing if the connectivity is working between two systems. In other words, the reachability of a host on a network.

Utility software is the one created for configuring, analyzing, maintaining, or optimizing machines. It supports computers’ infrastructure. Ping command is a very popular resource for diagnosis, and it’s available (built-in) on all operating systems.

Ping command syntax for Linux

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DNS propagation

Internet is a hard game. Managing a website or a network demands constant changes to your strategy. Expansion, to be more visible, efficient, competitive, etc., are common triggers of change. That directly pushes DNS modifications and daily challenges for administrators.

What’s DNS propagation?

DNS propagation is the time period that it takes to update DNS modifications all across the Internet.

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