Tag: DNS

Internet and DNS in Asia (Singapore, Hong Kong, Malaysia and more)

Martin Pramatarov / / DNS

Current Internet state in Asia

Let’s first talk about the internet in Asia Pacific region. According to the Statista, this region is the most important internet area in the world. There are more than a billion users, with the 3 most connected countries – China (731m), India(462m) and Indonesia (132.7m).

Despite the enormous numbers, there is still plenty of room for growth. The internet penetration there is 44.7%, so still more than the half of the people there don’t use the internet. There are many users, and more are yet to connect. This makes it an exciting market. With a lot of traffic, the need of DNS in Asia will just grow as well. So to provide an excellent service in Hong Kong or Japan you will need DNS.

DNS

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What is CDN (Content delivery network)?

Martin Pramatarov / / CDN

Everybody uses CDN (content delivery network). YouTube, Amazon, Netflix and many others are applying it in a massive world scale so you can enjoy your favorite content in a matter of milliseconds. But how does it work?

CDN

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What is DNS propagation? How to check DNS propagation?

Martin Pramatarov / / DNS

DNS propagation, you already know what DNS is, and if you don’t, you can check it HERE.
Now let’s see the second word – propagation. To propagate, it means to spread ideas, opinions among people and places (Cambridge Dictionary).

DNS propagation

DNS propagation

It is about the time it takes, to expire the cache in the recursive servers after you make your nameservers to point to new hosting. When you make the changes in your DNS records, they will get instantly updated in the authoritative servers. It will take extra time, for the data, to be modified in all the recursive servers along the way.

The connection passes through many recursive servers, including those in your internet provider (ISP). All of them have TTL (Time to live) which defines for how long they will keep the DNS cache with the DNS records. The DNS cache exists mostly for load balancing so that it won’t be so heavy on your nameservers and to make the whole process faster.

When a user uses their browser to open a web page for the first time, he or she will send a request all the way to an authoritative server. If it is not for the first time, the request will get an answer on the way in a recursive server, and if the data is still up to date, the user will get his answer quicker.

Basically, the DNS propagation depends on the TTL in the DNS records.

How to make the DNS propagation faster?

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What is Ping? How to use Ping?

Martin Pramatarov / / Tools

What is Ping?

Ping is a very universal command between all the operating systems. You can use it to test if you can reach your target and how much time it will take to do it. Ping sends Internet Control Message Protocol (ICMP) packets to the destination. Then it waits for the echo reply. It can show statistic for this request, errors and packet loss.

When you use this command, you will send few echo requests, usually 4. Then you will receive a result for each of them, that indicates if they were successful, how much data was received, the time it took for the response and TTL (Time to live).

Ping

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Primary DNS server

Martin Pramatarov / / DNS

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

Martin Pramatarov / / 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?

Martin Pramatarov / / DNS

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

Martin Pramatarov / / DNS

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

Martin Pramatarov / / DNS

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)

Martin Pramatarov / / DNS

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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