DNS and Cloud Technologies
Author: Martin Pramatarov
//We have already talked about load balancing. You can read the previous article HERE. Briefly explained, the traffic on the internet is constantly increasing. There are more devices connected and the data that circuit is more too. In order to manage all of this load, you need a load balancer that distributes it among the servers to reduce the load. Now we will focus just on one method to do so – Round Robin.
Continue reading “Round Robin Load Balancing. Simple and efficient”
//CDN is a network of servers geographically located in different areas around the world. They serve as a load balancer that redirect the traffic that goes to your website to the closest Point of Presence near you. It is like a shortcut. Now your visitors will not waste time to get to the web host service you use. They will be conveniently redirected to a cached data of your site, that is milliseconds away from them. They will open the pages fast and will have a better experience.
//Many network administrators use the traceroute command daily. It is a convenient tool that you can use under different operation systems – Windows (Tracert), MacOS, Linux (traceroute) and even on mobile (Android and iOS).
You can use traceroute, and see the full route that the packets take to their destination (domain or IP address). Apart from that, you will see the hostnames and IPs of the routers on the way and the latency, the time it takes for each device to receive and resend the data.
You can see which gateway is discarding your data and later you can fix it.
//Do you remember the time when we were reading the news in a printed newspaper and we were going to a video store to rent a VHS? The things have changed a lot ever since. Now you get the daily brief from an online portal and the content rental stores are all in the clouds. CDN is responsible for the global distribution of all that content. It makes it possible that all the viewers get their content in a matter of milliseconds, even if they live far away from the source.
Every media company who wants to be international relies on CDN. Youtube, Amazon, Netflix and many more can’t provide equal service in so many different locations without it. It can deliver quality 4k video without buffering (if the visitors have quality internet too).
//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.
Continue reading “Internet and DNS in Asia (Singapore, Hong Kong, Malaysia and more)”
//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?
//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).
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.
Continue reading “What is DNS propagation? How to check DNS propagation?”
//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).
//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.
//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.
Continue reading “DNS load balancing vs. Hardware load balancing”