What is a Recursive DNS server?

When you browse the internet, you don’t write IP addresses to go to the pages you want; you just write the domain. In the “backstage”, every request that you do, passes through a DNS query. It first goes to your internet provider’s recursive DNS server. If it can’t find in the cache, the information needed, it will continue to other recursive servers until it gets to an authoritative DNS server who can give the IP address of the required domain. Basically, it is a name server, that is a middle-man between you, the user, and the authoritative DNS server.

Tasks of the recursive DNS server:

1. Checks if the IP address is stored in the cache memory. There is a certain period of time, pre-defined by the domain’s owner called Time to Live or TTL. It says for how long the recursive server can hold the information. If it is still there, it will return the answer fast and won’t take further actions.
2. Searches for the IP address elsewhere. If it is not in the cache, it will continue the searching process until it gets to an authoritative server which has the information.
recursive DNS server

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Most significant DDoS attacks in the recent years

DDoS attacks are getting stronger, and they happen more often every year. With the technology advance, there are many more connected devices out there. Billions of mobile phones and many “smart” connected gadgets are easily hackable. As IoT (internet of things) is getting more popular, but not secure enough, this danger will keep rising.

DDoS Attacks

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Тools – DNS trace, Ping, Traceroute, Nslookup, Reverse lookup

In this article, we will use few different tools that will help you troubleshoot and monitor your DNS and network.

DNS tools

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DNS Spoofing (DNS poisoning)

Cyber-threats are behind every corner. Recently we wrote about DDoS attacks, and how hackers are using your computer and many connected devices to create a network of bots who can bring down even the best-protected network. Today we will review another danger – DNS spoofing.

DNS Spoofing

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Types of DNS records

Do you know what types of DNS records are out there? If you don’t know them all, don’t worry, we will explain them all in brief. By identifying them, you can easily manage your DNS plan in the best possible way.

DNS records

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What is Traffic Director?

Traffic director is a way to optimize and manage the traffic going to your domain by using geographical-based routing. Like this, your clients from Asia will get connected to your Asian servers; your European clients will connect to the closest servers they have in Europe and so on.
Traffic Director is a cloud-based implementation of Load Balancing (you can check our article on Load Balancing). It helps to improve the performance of your network. It can be incredibly useful for medium and large companies that need to deliver content to different parts of the world.

Some companies call this service traffic director, others global traffic director or GeoDNS director, but it is best known as GeoDNS, and that is why we use this term as the name of our service.

Traffic Director

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Why does DNS use UDP?

There are various ways of sending data over IP – TCP, UDP, DCCP, SCTP, RSVP and more. We will focus our attention on the two that are most used – the UDP (User Datagram Protocol) and the TCP (Transmission Control Protocol).

UDP

UDP and TCP

Both protocols are used to send packets of data over the internet. They do that on top of the IP protocol, which means that they direct the packets to IP addresses. They are treated very similar on their way from the users’ computers, through the routers and all the way to the end destination.

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What is Authoritative DNS server?

The authoritative DNS server is the final holder of the IP of the domain you are looking for. When you write a domain name in your browser, a DNS query is sent to your internet service provider (ISP). The ISP has a recursive server, which might have the needed information cached in its memory. But if the data is outdated, this recursive server need to find the IP elsewhere. It will try to find it in other recursive servers, but if it can’t, it needs to get the IP address from an authoritative DNS server.

Authoritative DNS server

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A case study of the top 50 e-commerce sites and their DNS

The recent Black Friday we again saw the news for record-breaking revenues and profits. Over the past few years, the web has gotten faster, according to Google, 53% of users will abandon a site if it doesn’t load within three seconds. By this, you can guess that for a shopping site, the speed of the website reflects its revenue. So, we want to see whether e-commerce sites got faster as well?

The DDoS attacks are also increasing. According to Kaspersky Lab 33% of organizations experienced a DDoS attack in 2017, compared to 17% in 2016. So we also want to know if the top shopping websites are well prepared for future attacks.

In this article, we will check with our DNS tool all of the top 50 E-Commerce websites. We will see if their speed and DDoS protection is fine or they will need to improve. Based on our research we will make recommendations how these websites can improve.

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