Friday, July 19, 2019

What is DNS? Definition, Function, and How It Works

DNS server is not responding.
You must have once or twice met a message as above. Such messages usually appear in the browser when your PC is not connected to the internet. Sometimes, similar messages also appear when you type the domain incorrectly into the search field.
What is DNS? Definition, Function, and How It Works
So, what is a DNS server? If you are curious about the answer, don't move from this article. Because here, we will explain in full what DNS is, its functions, its parts, and of course how it works.

What is DNS?
Domain Name Server or DNS is a system that connects Uniform Resource Locators (URLs) with Internet Protocol Address (IP Address).

Normally, to access the internet, you need to type the IP Address of a website. This method is quite troublesome. Because, this means, you need to have a complete list of IP addresses of websites visited and enter them manually.

DNS is a system that summarizes this work for you. Now, you can just remember the domain name and enter it in the address bar. DNS will then translate the domain into the IP Address that the computer understands.

For example, you want to access Google. Instead of writing 172.217.0.142 into the address bar, you just enter the Google.com address.

DNS function
From the explanation of what DNS is, you can certainly figure out how the DNS actually functions. However, to make it clearer, here we describe three DNS functions:

Request information on the IP Address of a website based on a domain name;
  • Request URL information for a website based on the IP Address entered;
  • Looking for the right server to send email.
Pretty simple, right? However, behind this simple innovation, you can surf the internet easily and pleasantly.

After discussing the outline of DNS functions, in the next section I will explain how the DNS server works.

DNS Parts
The basic principle of how DNS works is by matching the name of the URL component with the IP Address component. Each URL and IP Address have parts that explain each other to each other.

If you find it hard to imagine the technique, just think of it as an activity looking for books in the library. When you search for books in the library, you will usually be given a code that explains the location of the book.

The library code is called Dewey Decimal System (DDS). Usually it consists of the topic code of the book, the author's last name code, and the published year code.

Approximately the same principle is applied in DNS. To understand it more deeply, you need to know the parts of the URL arranged in the DNS hierarchy. Just like the library book code, each part explains the domain part.

One obvious difference is that the library code starts from the front. On the other hand, the code that applies to DNS is sorted from behind. Therefore, we will trace these parts of the DNS from behind.
  1. Root-Level Domain is the highest part of the DNS hierarchy. Usually it is a dot (.) At the very back of a URL.
  2. Top-Level Domains are extensions that are on the front of the root-level domain. There are two types of TLDs that are commonly used. Both are the Generic Top-Level Domain (GTLD) and Country Code Top-Level Domain (CCLTD).
  3. GTLD usually explains the nature of the institution of the web owner. Say, websites for commercial purposes usually have a .COM extension. Then,. EDU for educational institutions and .GOV for government institutions.
On the other hand, CCLTD is an extension that explains the origin of the site owner. For example, the suffix .ID for Indonesian websites. OR for Australia, .UK for England, and so on.

Second-Level Domain is another name for the domain itself. It is often used as an institutional identity or branding. In the case of the URL en.wikipedia.org, what is meant by SLD is wikipedia.

Third-Level Domain or subdomain is part of the main domain that stands alone. If the domain is likened to a house, a subdomain is one of the special spaces in the house itself.

Hostname or can also be called a scheme. This is the part that starts a URL. This section shows a function of a website or page. The most widely used examples are HTTPS or Hypertext Transfer Protocol Secure.

How DNS works
DNS works in stages. Begins the process of requesting information or DNS queries. Then proceed with other stages such as DNS recursion, root nameservers, TLD nameservers, to the authoritative nameservers.

Without further ado, here is an explanation of how DNS works. Everything is sorted step by step.

DNS Query
DNS Query is a technical term for requesting information about IP Address. This stage starts when you type the URL into the address bar.

The DNS server then searches for information on filehosts. If the information sought is not found, the server will try to find the information or record information that has been recorded in the system (cache).

In this initial stage, there are three types of DNS queries. The three are recursive queries, iterative queries, and non-recursive queries. Below, you can find the meaning:

Recursive query
The user gives which hostname then the DNS Resolver must provide an answer. There are two possible answers given. First, DNS will provide relevant information after searching in the Root Server or Authoritative Name Server. Second, the browser will display an error message because information cannot be found.

Iterative query
The user enters the hostname. The DNS resolver will look for the relevant cache in memory. If it doesn't work, the DNS resolver will look for information in the Root Server and the Authoritative Name Server that is closest and relevant to the DNS zone.

Non-recursive query
This is the fastest information retrieval process. This type does not require searching in the Root Server or Authoritative Name Server because the search data is stored in the cache.

DNS Recursor / DNS Recursive Resolver
DNS recursor is the first stage of information search. When a user enters a URL and does not find valid results in cache, the system will search for information in the cache of the internet provider or internet service provider (ISP).

Root Name Server
Say the information you are looking for cannot be found at the ISP. Then later, the system will look for the information you need to root the server.

Root name server is a kind of database that answers questions about domain names and IP Address. This server does not have the right answer for the information sought.

However, this server can forward information requests to those who know better. In this world, there are 13 root servers that work. The root server is alphabetically sorted from A to M.

Such root servers are managed by organizations such as the Internet Systems Consortium, Verisign, ICANN, the University of Maryland, and the U.S. Army Research Lab.

TLD Name Server
From the root name server, the system will read the type of information sought from the top-level domain. Each TLD such as .COM, .ORG, .EDU, .ID, .AU, and so on has a specific server.
By reading this information, the system can continue searching information to the server that actually has the data sought.

Authoritative Name Server
After finding out where the server is desired, we arrive at the authoritative name server. This type of server has all the complete information about the destination website.

When the requested information matches the results, the browser will display the website or page you requested at the beginning. Of course this search result has a certain time period.

This search process will be repeated to ensure the information displayed remains up-to-date. But, of course, some of this information is stored as a cache on the device just in case the query process runs fast.

Kinds of DNS
Information requested by the user in the DNS system is called the DNS record. There are several types of information that can be requested in the DNS system. Here are the 10 most common DNS records:
  1. A Record or Address record - stores information about hostname, time to live (TTL), and IPv4 Address.
  2. AAA Record ─ stores information about the hostname and its relationship with IPv6 address.
  3. MX Record ─ records an SMTP server that is specifically used to send e-mail messages to a domain.
  4. CNAME Record ─ is used to redirect a domain or subdomain to an IP Address. Through this one function, you don't need to update the DNS record.
  5. NS Record - refers to subdomains at the authoritative name server you want. This record is useful if your subdomain in hosting is different from the domain.
  6. PTR Record ─ gives permission to the DNS resolver to provide information about the IP Address and displays the hostname (reverse DNS lookup).
  7. CERT Record - stores an encryption certificate or security certificate.
  8. SRV Record - stores information related to the location of communication, such as Priority, Name, Weight, Port, Points, and TTL
  9. TXT Record - brings and transmits data that can only be read by the machine.
  10. SOA Record ─ the part that appears at the beginning of the DNS zone document. The same section also refers to the Authoritative Name Server and complete information about a domain.
Already Understand, What Is DNS?
Through this article, you know what DNS really is. In essence, DNS is a system that makes it easy for you to browse the internet. You don't need to remember the website address in numbers. You simply write down the domain name that you want to open and DNS will translate it to the IP address of your destination.

In this article, you also learn what DNS functions and parts there are. No less important, you understand how DNS and the internet work. All of the above processes can run in a fraction of a millisecond. Magic, isn't it?

If you have questions about DNS and other internet accessories, don't hesitate to leave a comment below. Don't forget to subscribe to Niagahoster Blog to be the most updated about the latest internet info and trends.See you in the next articles


EmoticonEmoticon