Category: Network

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.

CDN – What is it and how does it work?CDN – What is it and how does it work?

CDN – definition

The term CDN refers to a “content delivery network.” It’s a network of servers that spans a large geographic area and has extremely particular server locations. The purpose is to cover the territory from which possible tourists may originate thoroughly. To have servers that cache data (code, photos, movies, and so on) as close to visitors as possible. Visitors will receive better and faster service as a result of this. The CDN’s other benefit is load balancing, which reduces the workload on the central server.

How does it work?

CDN works in a simple way. It saves a cached version of the demand information in multiple points of presence (PoPs). Every PoP also has a caching server in charge of providing content to users in its immediate area. For example, users in France will access your site through a local France PoP if you own an e-shop in the United Kingdom. Their queries and your site’s responses will not have to go across continents.

Every CDN has servers located at Internet exchange points (IXPs). For its part, Internet service providers connect to these key locations, for example, to provide access to the traffic generated on their various networks. Connection to these IXPs gives CDNs significantly increased speed and connectivity to a wide range of destinations. This saves costs and transit times in high-speed data delivery for content delivery network providers.

Who is the CDN for?

It is for everyone! Yes, almost everyone can implement CDN. Take a media corporation, for example. If you already have one, a content delivery network could be the key to expanding your distribution. It might also be helpful for e-commerce sites, especially if they operate in a number of markets, such as the United States. Alternatively, if different countries, such as the European Union, are your target market, it may be a good match. Blog sites, news sites, online services, and many other types of websites are not exempt. It is entirely dependent on your requirements.

Benefits

  • A CDN shortens the time it takes for a website to load and minimizes latency to the absolute minimum. This is because you have a cached version of the requested content on a server near to where the origin of the request. This makes the transmission of the necessary materials to load it much faster (images, videos, javascript files, HTML pages, etc.).
  • CDN increases the availability and redundancy of your data. Each of the servers in a content delivery network can save a cached copy of your information. Of course, things happen, and hardware can fail, but this redundancy can ensure that your website’s information is always available.
  • Content delivery networks can help to improve security. They can efficiently distribute traffic since they are huge networks. DDoS protection, security certificates, and other features are also available from reputable vendors.

Conclusion

One of the most important criteria in determining the efficiency of a website is its speed. With CDN, you may get better performance and a better user experience. Use it, and you’ll see the benefits right away in your wallet!

Round-Robin DNS – Everything you need to knowRound-Robin DNS – Everything you need to know

What is Round-Robin DNS?

Round-Robin DNS is a mechanism for administrating the incoming traffic. 

This technique is based on the time of arrival of the user request and the actual number of servers that you have. Simply you create several A or AAAA records with different IP addresses (IPv4 and IPv6) that correspond to the multiple servers. Each one of them stores a duplicate of the information for your website. So, whenever a user requests your domain name, the authoritative name server, storing the A or AAAA records, is going to provide the next in rotation turn A or AAAA records from those you created. The users are going to be automatically directed when they are desire to reach your website. The exact moment when they reach your DNS name server is important for the precise order.

Let’s break down the process a little bit more. 

In a case you have 5 users and 3 servers:

User 1 connects to server 1.

User 2 connects to server 2.

User 3 connects to server 3.

At the moment when user 4 requests to visit your website, the circle will start again. 

User 4 will connect to server 1

User 5 will connect to server 2 and so on.

Why should you use it?

Round-Robin DNS handles the traffic to your website and reduces it. As an outcome, the user experience of your customers is going to be drastically improved. In addition, the network is going to be less saturated, and its performance is going to be better.

This load balancing mechanism allows modifications. That means in case your servers are not equal and one of them is better than the rest, you can set the mechanism in the best productive way. The weaker servers are going to receive less traffic.

Round‑Robin DNS algorithm types

  • Weighted Round-Robin – You can choose specific criteria and assign the particular weight to every server. Typically, administrators use the server’s traffic‑handling capability. The higher the weight, the bigger the number of user requests the server is going to receive. 
  • Dynamic Round-Robin – A weight is assigned dynamically to each server. It observes real‑time data about the servers’ load and unused potential.

Benefits of Round-Robin DNS

  • It is very simple and easy to install and set up the Round-Robin DNS.
  • Balancing the traffic improves the security and could prevent a DDoS attack in progress.
  • Round-Robin DNS is a pretty cost-effective option.
  • It satisfies the users’ expectations and handles high volumes of traffic efficiently.
  • You can easily optimize the functionality of your network to make it healthy, fast, and safe.