What is DNS and how does it work?rouzbeh kalhor
DNS, which stands for Domain Name System, is one of the bases of Internet, and most of us use DNS during the day without knowing it. In this article, we tried to examine the concept and performance of DNS and some of its advantages and disadvantages. We use DNS in many of daily tasks, such as working with our cell phones, checking email, and surfing the Internet. But what is DNS?
What is DNS?
DNS is like a phonebook for the Internet. Just as you use a phonebook to call others instead of memorizing their number, DNS acts like a phonebook and there is no need to memorize IP addresses. As you know, computers use numbers, or IP addresses, to connect to each other.
Domain Name System is a distributed list that converts human-readable domain names such as www.respina.net into legible numbers for computers, i.e. IP addresses. The same is true of DNS, where DNS is a system that organizes the domain name of the web and makes it more accessible to anyone who wants to connect to the network.
How does DNS work?
When you visit a website, your computer follows a series of steps to convert a human-readable web address into a machine-readable IP address. This happens every time you use a domain name, whether you are browsing a website, sending emails, or listening to music on the Internet.
Each website can match more than one IP address. In fact, some websites have hundreds or more IP addresses that match a single domain name. As a result, the DNS system needs to convert IP addresses to readable domain names, as it is more difficult to remember a large number than a fixed domain name.
If there is only one directory for a website, then when the number of requests to visit a website increases, it will take a long time for your request to be answered. Instead, DNS information is shared on many servers, but is also stored locally on clients’ computers. It is possible to visit a website several times a day. Once stored in the cache, you no longer need to resolve the domain name with the IP address each time. As a result, the number of times you need to use DNS is less than the number of times you search a website in the browser.
DNS uses a hierarchical database that contains information about the domain name. Suppose you enter a domain name in your browser. The first thing your computer will do is send a request to the operating system’s local DNS server to check if the answer you need is stored in the computer’s cache. If it is not found in the cache, your request will be sent over the Internet to one or more DNS servers, which are generally communicated by your ISP. If the required information is not found on these DNS servers, the request will be sent to other external servers.
What are the benefits of DNS?
The main advantage of the DNS system is that it makes the use of Internet much easier. It would be very difficult if we had to maintain all the IP addresses we wanted to access to visit the websites. With DNS, you no longer need to memorize this number string and it is suitable for categorizing, archiving, and optimizing search engines.
Another notable advantage of DNS is its stability. IP addresses may change for a variety of reasons, so if you want to access a website, not only you need to know its IP address, but it also needs to be up to date. The DNS system has the task of updating IP addresses in a very fast and consistent way and making our access to websites easier.
DNS can enhance infrastructure security, and it can also provide dynamic, secure updates. It is more reliable and can deliver messages to users without failure. DNS enables you to specify the technical performance of the database service. It can also define the DNS protocol, the exact specifications of the data structure and the data exchange used in DNS. In fact, DNS is used as a kind of load balancer or an additional layer of security.
What are the disadvantages of DNS?
In addition to all the advantages and applications of DNS, there are also some disadvantages. One of its main drawbacks is DNS Attacks, in which an attacker replaces a real DNS address with a fake one for fraudulent purposes and tricks users into unauthorized addresses. This is usually done to obtain banking information or other important user data.
If the malware has changed your DNS server settings, entering the URL may take you to a completely different website or to a website that looks like bank website. It may record your username and password and collect the information needed to access your bank account for the abuser.
Malware hijacks some DNS servers to redirect you from popular and high-traffic websites to fake and ad-hoc viral websites, and creates the misconception that to remove viruses from your computer you have to download and install programs which are in fact malwares.
To avoid such problems, it is necessary to install reputable antivirus programs on your system and avoid entering websites that look different from your requested website. Also, avoid entering your personal and banking information on unreliable websites.