Tag: domain name

What is the purpose of DNS cache?What is the purpose of DNS cache?

In this post, you will discover the primary purpose of the DNS cache and how you can delete it. Let’s begin.

DNS cache – definition

The DNS cache is a type of temporary cache memory used by devices and DNS resolvers to store all previously used DNS records for the searched domain names. For example, the IP addresses of domain names and subdomains, data for their services, information about their email server, verification and authentication information, and so on are all contained in these records. Based on each DNS record’s TTL (Time to Live) value, the data will be saved in this DNS cache.

How does it work?

It works in a simple way. A DNS lookup is triggered whenever a user requests a domain name. Then the user’s device will initially look in the DNS cache built into its operating system (OS). It’s a database where distinct DNS records and their TTL values are stored. As previously stated, that TTL is established by the domain’s DNS administrator. The needed DNS entries can be found immediately there if the TTL hasn’t expired. The request will be fulfilled, and the domain will load extremely quickly. However, if the TTL has already passed, a new lookup will require additional time for the entire process to repeat.

This indicates that a DNS recursive server will accept the user’s request and request DNS records from other servers. First, it will query the root server, which will lead to the particular TLD server that should be searched, and then the recursive will be sent to the authoritative name server, which will finally supply DNS data (records).

The information will be transmitted to the user’s browser so that the domain can be loaded. Those data will be cached in the recursive server’s DNS cache, and the user’s device (computer, tablet, or mobile) will have access to them for as long as their TTLs allow.

Could you delete a DNS cache?

Yes, you can do it yourself. The clearing method varies depending on your operating system and browser, which may have its own DNS cache.

  • On Windows

So, first, find the Command Prompt and open it. Then type the following command: 

ipconfig /flushdns

Then you have to see a confirmation message. This is because the DNS has now been cleared.

  • On Linux

Launch the Terminal. Then run the following command:

sudo systemd-resolve –flush-caches

After that, type your sudo password and hit Enter. The DNS cache is deleted!

  • On macOS

First, open the Terminal. Then type the following command:

sudo killall -HUP mDNSResponder

After that, type your password and press Enter. Ready!

Okay, we see how to clear the DNS cache on different operating systems. Now, let’s see how to do it in different browsers:

  • Google Chrome/ Edge/ Opera

Chrome:/net-internals/#dns – copy this line. Then paste the line into your browser’s address bar. Enter your password. So now, on the page, look for “Host resolver cache” and then click “Clear host cache.” Ready!

  • Safari

In Safari, you can delete your cache by a different method type. First select “Advanced” from the “Preferences” menu. Next, look for “Show develop menu” in the toolbar there. Then find “Develop,” followed by “Empty Caches.” Ready!

Conclusion

In conclusion, we can agree that the DNS cache is a helpful tool for speeding up and streamlining the DNS resolution process. However, if necessary, you can delete it by following the steps above, depending on your operating system.

DNS record types – Definitions & PurposesDNS record types – Definitions & Purposes

The whole complicated Domain Name System has different DNS record types. Without them, this system will not be able to function. Why they are so important and what are their primary purposes we are going to see today in this article. 

DNS record – definition

Before exploring different DNS record types, we will see what the term DNS record means. They are text instructions situated in the zone file. Their primary purpose is to allow domain names to be resolved to IP addresses. They are so light and easy for modifications if they are necessary. We use different record types because computers are not like us humans and can’t understand the texts. So that’s why we translate this information in their language via DNS records. In other words, they translate the written information into numbers that machines can understand.

What are the most popular DNS record types?

Referring to the above, there are lots of DNS record types. Each one performs a specific job that is crucial for the proper operation of your Domain Name System. We’ll look at five of the most important ones, which are: 

A record

The A record is perhaps the most common and popular DNS record type. Its major goal is to link a domain name to the IP address that corresponds to it (IPv4 address). A user requests the A record whenever they wish to access and explore a specific website (domain name). It must be pointed to the correct IP address.

The A record is an essential aspect of the DNS setup. The domain name would be unable to be resolved if it was not found in the DNS zone.

SOA record

The next vital DNS record is SOA, representing the start of authority. It’s where the zone’s administrative data is kept. It is the initial DNS record in a DNS zone file, and it also establishes the zone’s general attributes. It also contains information on zone transfers, such as the refresh rate, retry rate, and administrator’s email address.

The SOA record acts as a control record with a serial number that indicates whether a new update is available. When the Secondary DNS servers notice a change in the number, they will update and obtain the most recent information.

PTR record

Another essential DNS record is the PTR record. If you want to send emails to anyone without difficulty, you’ll need it. The PTR record, also known as a pointer record, serves the opposite purpose as the A record. It connects a domain name to an IP address. When you send an email, your recipient will want to double-check that it was sent from your domain name. As a result, here the PTR record comes. If you make a mistake configuring the A record and the PTR record, your emails will most likely end up in your recipients’ spam folders.

MX record

The MX record, which stands for Mail Exchanger record, is another crucial DNS record type. It aims to direct the email server in charge of receiving emails for a particular domain name. It contains the domain name that points to the incoming mail server’s hostname. In addition, it should be noted that it must point to a hostname rather than an IP address.

In case of failure, you can build up a backup by creating numerous MX records with different priorities. It is critical for you to be able to receive emails correctly.

TXT record

We can’t skip the TXT (Abridged from text) DNS record. It is very versatile. In a text format, it provides information to sources outside of the domain. A type of TXT record is the SPF record. Mail servers are using it to decide if the mail source is trustworthy and comes from the correct domain. 

The TXT records could be used for different verification and authentication methods. Increasing the level of trust in your domain and emails is vital for your internet reputation.

Conclusion

Now, you can safely say that you are familiar with the fundamental DNS record types. They are critical for your Domain Name System to run smoothly and without a hitch. If you configure them well, you will have no problems.

DNS resolution – Essential behind-the-scenes processDNS resolution – Essential behind-the-scenes process

DNS resolution – Definition

The DNS resolution is a fundamental process that resolves a domain name to its IP address (IPv4 or IPv6). Without it, the entire Internet would work in a completely different way. However, it occurs behind the scenes because regular users don’t even notice that it is happening. People are used to typing a simple domain name, and the desired website is loaded in their browser. However, the user’s DNS query is actually traveling through several separate servers until it receives a full answer. 

DNS resolution process explained

Regular users are used to connecting with their favorite websites in the blink of an eye. However, the entire DNS resolution process actually takes a long path. So, let’s’ explain a little bit more about the steps of this process, which begins with the user’s desire to visit a precise website for the very first time. 

  1. The user makes a DNS query by writing the domain name into its browser’s address bar. That way, the DNS lookup for the needed IP address begins.
  2. The recursive DNS server obtains the DNS query and checks in its own DNS cache memory. The required IP address could still be available there. In case it is not found there, the recursive DNS server proceeds to the following steps. 
  3. Тhe recursive DNS server proceeds and queries the Root server, which is on the top of the DNS hierarchy. The Root is able to provide information only for the location of the TLD (Top-Level Domain) server, such as .info, .net, .com, and so on.
  4. The DNS query is redirected to the TLD (Top-Level Domain) server responsible for the precise domain name. This server holds information about where is the needed name server for the domain.
  5. The recursive DNS server (DNS resolver) proceeds and requests information from the authoritative DNS server of the domain. This server carries the needed data (IP address) of the domain name, and it is the one capable of delivering an authoritative answer to the DNS recursive server.
  6. The recursive DNS server receives the information and contacts it back to the browser of the user. Additionally, it is going to store the IP address in its DNS cache memory to provide a quicker answer in the future.
  7. The user receives the IP address (IPv4 or IPv6), connects with the desired website, and caches it in the DNS cache.

So now you understand that the DNS resolution is an extensive process with several steps. Yet, at the same time, the user sees it as a few seconds.

Why is it important?

The DNS resolution process is crucial for humans. If it does not exist it would be a challenge for regular users to use the Internet and connect with their favorite websites. Back in the days when DNS (Domain Name System) did not exist, all IP addresses were saved in a single Host file. However, that was not practical anymore due to the fact that the devices wanting to connect to the Internet got a lot more.

Thanks to the development of DNS and the process of DNS resolution, we are easily accessing each website that we want by simply typing the domain name. We are not required to memorize complicated IP addresses.