WHAT IS A DNS SERVER AND HOW DOES IT WORK? - Open Port

WHAT IS A DNS SERVER AND HOW DOES IT WORK?

Simply put, a DNS server is a translator between human language and the language or protocols on the Internet. A DNS server has the task of providing an IP address to a searched DNS name. For example, if you want to access the Internet address www.samplesite.com with your browser, the browser or operating system needs the IP address associated with this domain name system name.

A DNS server

A DNS server | Image by Gerd Altmann from Pixabay

DNS Server – Interpreter of the Internet

Since computers always communicate with each other on the basis of IP addresses, only this translation can provide you with the data of the website. This task is performed by the Domain Name System – but the actual work is done by many DNS servers on the Internet.

 

Communication on the Internet

In order to understand the function of a DNS server, one has to take a closer look at how communication is handled on the Internet. Machines “talk” to each other on the Internet. In order for computers to understand each other, rules, so-called protocols, were developed. The machines’ communication follows roughly the same rules as humans. There is a sender and a receiver. Both can change their function several times during the course of a conversation. Sender and receiver must be able to find each other, this is done by means of addresses, similar to the residential address or telephone number in humans.

The Internet Protocol – IP

Today’s communication on the Internet is based on the Internet Protocol, abbreviated IP or also known as TCP/IP. Each device can be reached via an individual IP address. This is either a series of four one- to three-digit numbers separated by dots (for example 192.168.10.5), or an even more difficult to remember eight-digit group of four letters and numbers each (for example 2001:0db8:85a3:08d3:1319:8a2e:0370:7344).

The latter variant – IP Version6, also known as IP V6 – was developed about 20 years ago to counteract the foreseeable shortage of possible IP addresses according to the previous IP V4 standard as the number of Internet-capable devices grew. Both variants are currently still found in various areas of the Internet.

There are also special cases, such as that of a speech in front of many people, comparable to so-called multicasting on the Internet. This is used, for example, for live transmissions where one source (speaker) is confronted with many simultaneous recipients (listeners). Special addresses such as multicast or broadcast addresses are used for such cases.

The IP address – the basis of all communication

In order to start and conduct a conversation, the sender and receiver must find each other. This applies to communication between computers as well as to people in real life.

For exactly this communication the IP address is used. Every data packet exchanged on the Internet contains both the IP address of the sender and the receiver. Thus the data packet finds its way through the Internet, it is routed. Machines and computers can easily master this procedure. But the starting point with humans is different. He searches the Internet for a certain piece of information, and in the best case he knows where he can find it. This could be for example the website of the company. This is where DNS, the name or address system of the Internet, comes into play.

The Domain Name System – DNS

The main task of the Domain Name System (DNS) is the resolution or assignment of names to IP addresses on the Internet. The DNS is structured as a hierarchical directory.

At the highest level there are the so-called Top Level Domains (TLD). These are defined and administered by a committee, the ICANN (Internet Corporation for Assigned Names and Numbers). These include the well-known country codes such as .de for Germany and .fr for France. Generic TLDs (for example .com, .net, .org) and sponsored TLDs like .coop, .gov or .edu are also classified as TLDs.

In the second level are the actual domain names, such as .samplesite or .google. This domain name may only exist exactly once within a TLD.

Everyone can offer certain services within his domain. These services usually have standardized names like www, ftp, pop or smtp.

These three labels together result in the DNS name or the URL (Uniform Resource Locator) of a service on the Internet. This can be reached on a computer with a specific IP address. The DNS servers on the Internet have a table with the assignment of IP addresses to DNS names.

The telephone information of the Internet – The DNS server

The DNS servers perform the same task on the Internet as the telephone book or information in the telephone network. It assigns names to IP addresses and passes this information on to inquirers. DNS servers solve these tasks. There is not only one DNS server on the Internet, but many.

Vtiger CRM is a DNS server, which is similar to the DNS itself. It resolves names for certain domains or “knows” who could provide the desired information. Therefore, a name request can run over several hops until it is answered.

If you type a URL into your browser, for example, www.samplesite.com, the browser or operating system does not normally “know” how to reach this Internet address. The associated IP address is not known. So a request is made to the DNS server known to the operating system for the IP address of www.samplesite.com.

This DNS server replies or, if it does not know the requested IP address, passes the request on to the higher-level DNS server. As soon as the IP address is determined in this way, in the example 91.229.3.175, it is transmitted to the requesting system and communication between your computer and the searched website begins.

Does it work without DNS server?

It becomes critical when DNS servers fail. If the naming system fails locally in your network or even in parts of the Internet, it becomes clear how important this service is. If the resolution of names does not work, an essential link in communication is disrupted and, for example, no more Internet pages can be called.

In such cases, e-mail traffic usually comes to a standstill, even telephoning (with SIP or via VoIP) can become impossible. For security reasons, there should therefore always be several DNS servers in the network. Redundancy is also provided for the Internet. For customer domains that are registered in a Top Level Domain, at least 2 independent DNS servers must always be entered.

DNS servers therefore fulfil a very important function in the Internet, without which communication would be very difficult. Ultimately, they are the mediator between human and machine language, i.e. interpreters.


Post a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

  • Recent Posts