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DNS is a system used on the internet that keeps websites and domains working, in addition to making life easier for users — like loading your website faster. The problem is that most users don’t know about its existence, much less about the importance of its proper functioning.
In fact, many times, some of the failures that occur when you want to access a website — even your own website — and you can’t, are due to problems with DNS.
That’s why it’s important that you understand how it works and how to do a proper DNS check, as well as what checking tool or DNS Checker you can use to simplify your life with this task. Let’s see…
What is DNS?
DNS stands for Domain Name System and it’s a whole system whose task is to translate “IP addresses” into “domain names” that are easier for people to remember.
IP addresses are part of the protocol that DNS is, which is used by computers and a whole series of electronic devices — yes, including your smartphone — to communicate over the Internet.
Think of it like a phone book. Even though this example is dated and some people today have never used a phone book, this is a good analogy. If you want to call Bob, you need to look for Bob’s phone number. You can’t just tell your phone to call Bob (we know, you can do this in modern times), it needs to have a phone number to call. This is how it works with domains too.
It’s easier to understand with an example:
The IP address of the server that a website lives on is 126.96.36.199 (the website’s phone number) — it’s just an example — would be much more difficult to write and remember than the domain name pagemend.com, which is registered in this way on the public and private organizations that make up the infrastructure of the Domain Name System internationally.
So, when you want to access pagemend.com, you open your web browser and instead of typing 188.8.131.52, you type the domain name of pagemend.com; but besides this, DNS also contains additional information related to domain names.
What are DNS servers and how do they work?
DNS servers are a fundamental part of the Domain Name System and the internet in general. There are several types and they work through a hierarchical structure, with a distributed system and through a client <—> server model.
When consulting the DNS of a domain, the query points first to the root or main DNS server, which are actually several servers distributed in different places that are identified with letters — A to M.
These servers are perfectly synchronized at all times, so what DNS servers do is attend and respond to the different DNS queries of all domains, starting with the classic ones that end in .com, .net or .org, to the newest ones like .xyz, .organic or .echo, just to name a few.
What is DNS propagation?
Propagation of DNS is basically the time it takes for the DNS information to be dispersed to the different servers of the Internet. This process can take between 12 to 48 hours, depending on several factors.
Each server on the internet stores a series of DNS records in their cache from their providers. The objective of the cache is to accelerate the speed at which you can access a website.
That means that each server makes its own copy of the main or master records, this with the idea of accessing these records locally and not having to search for them over the network, which would slow down the process.
The problem is that each company or Internet provider that stores these records, only updates them every certain number of days and there is no standard on this matter.
So, updating the server’s cache is called propagation, and when it’s completed, everyone can visit the website without problems.
What are DNS records?
DNS records are files that tell a DNS server which IP address a specific domain is associated with – like a phone book matches names with phone numbers.
As mentioned before, instead of typing the IP address of a web server, you only enter the name of the website or domain name to access that website.
It turns out that it’s the web browser itself — Firefox, for example — that consults with the DNS server of your device’s operating system, which public IP address corresponds to that domain name that you’ve written.
In addition to this, DNS records also tell DNS servers how to handle the requests that are sent to each domain name; for example, whether or not the information on a specific website should be displayed, something widely used by institutions and companies to block access to their online systems.
In short, DNS records are like different strings of letters that are used to indicate certain actions to the DNS server. These strings are also known as “DNS syntax”.
The list of DNS records is extensive, but let’s see a hand of examples:
* A: This record refers to the IPv4 address of a web server and is the most common in DNS servers.
* CNAME: This record refers to an “alias” of another domain. That is, its function is to make a domain be treated as an alias for another domain. As in the case of associating new subdomains with existing domains.
* MX: This refers to a list of email exchange servers that must be used for a specific domain.
* TXT: This refers to a text; that is, it allows you to insert text into the DNS record. This is useful for leaving notes with information about the domain.
* NS: This record indicates which domain name server is authorized for a particular domain.
Note that it’s important for DNS server administrators to know what each record is for and what can be done with each one of them.