Primary DNS server

We have already talked about what is DNS and what is a Secondary DNS, this time we will focus on the Primary DNS server. There is a DNS hierarchy in which the Primary DNS server is taking the central spot. It has the latest and full information, in comparison with lower level DNS servers who has just a cache of this information and with an expiry period.
Primary DNS

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DNS load balancing vs. Hardware load balancing

Why do we need load balancing?

With the massive increase of the internet traffic each year, it is getting harder to provide a sustainable service for all the millions of clients without having some downtime. For this purpose, you need to apply a model of load balancing, that will reduce the load caused by the countless users trying to reach your website or use your application.

Another reason why you need to use load balancing is the rising number of DDoS attacks. To evade them you will need to spread the traffic to as many as possible servers that you have. That way, their combined efforts can resist the wave of high traffic.load balancing

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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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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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