Understanding DNS: Essential Knowledge for IT Professionals

What Is A DNS Server - EgnUnited.com

As the Internet expanded and the number of host computers increased, finding non-duplicate netbios was a huge problem, and its database file management failed. The existence of these problems led Microsoft to introduce the DNS service in 1984. All that you need to know about DNS service! Reviewed byAliShanezaronOct 22Rating: 5.0

Setting up the proper DNS service is one of the first steps that is required in the design of the site and does not necessarily allow any site to be launched without proper and proper implementation of these settings. Before that we can use our site and start SEO and optimization as well as advertising activities, we need to set our site to your preferred domain name. To do this, it’s best to have some familiarity with the DNS service .

The DNS service has a tree structure and is a “Distributed Database,” which is deployed on multiple machines. Most companies and institutions have a small DNS server in their organization to ensure that computers find each other without any problems. This tree structure consists of names called domain names (Domain Names). Each domain is divided into smaller domains. All of these domains form a tree, and the tree leaves show domains that lack domains.

Top-level domains are two types: general and country. Public domains are com (commercial), edu (educational), gov (federal government), mil (military), net (network servers) and org (organizations).

In the DNS service, the user’s computer attempts to send a DNS-based request to a server in order to locate an address. For example, if you type in the browser at https://clickaval.com, a DNS -based request will be issued from the user’s system to a DNS server whose address is already registered in the system.

Named name analysis process in DNS service

To enter a site on the Internet, you must send a request in one package. In the packet header, there is only the destination IP address field and it is very difficult to maintain these addresses. Hence, the names of the medicine were used like URL names and the names of the IP addresses were converted using name resolution. When the user returns the name of the site in the browser’s address field to convert that name to the IP address, it first comes to its Resolver Cache, which is the same as the Hosts. This file is located in Windows on the following path:

C: \ Windows \ System32 \ driversletc

An example of the contents of this file is as follows:

.Copyright (c) 1993-1999 Microsoft Corp #


.This is a sample HOSTS file used by Microsoft TCP / IP for Windows #


This file contains the mapping of IP addresses to host names. Each #

entry should be kept on an individual line. The IP address should #

.be placed in the first column followed by the corresponding host name #

The IP address and the host name should be separated by at least one #

.space #

 Additionally, comments (such as these) can be inserted on individual #

.lines or following the machine name denoted by a ‘#’ symbol #


: For example #


102.594.997 #

38.25 63.10 #

x.acme.com localhost

Understanding DNS - EgnUnited.com
What is a DNS Server – EgnUnited.com

If the computer could not find the address in the referencing file, it will send a ready request and send it to its network DNS server. The service provider receives the package and initially refers to the area defined in the contract. If no answer is found in these areas, it will begin to search the DNS Server Cache.

After the completion of work, if there is still no response, requests are sent to roots (Root Hints), which are in fact the same Internet DNS servers.

If the DNS server fails to respond to the user, it will inquire within the process of the higher level Internet service provider’s address.

In general there are three ways to query:

  • You’re back
  • Repetitious
  • Reverse

Recursive: This method is usually performed between the user’s computer and the DNS server, or between several DNS servers by setting the forwarder’s option.

Duplicate:   This is usually done between DNS servers. After sending the request to the root, if the root does not have the host IP address, it returns the server’s URL that contains the extensions of the com file. After that, the server will make the name 1 communicate with the COM server and request the IP request. This server also does not have the IP of the computer, but the IP will return a DNS server at the requested domain. The server then goes to the corresponding domain and receives the IP address from it. It then returns it to the customer in the requestor.

Reverse: This method converts an IP address to a host name. If a DNS server knows the IP address of a machine, it can find it by its name.

Areas available in the DNS service

After the DNS service is launched on the server, each domain must have a domain (part of the domain name domain name, called “domain management”), to be created separately, and records are available for each domain. Among the areas that can be created in this service include:

  • Primary Zone Primary Zone: This type of area is the same as the original area and is created in the original DNS server and the records are updated there. The records of this area are editable.
  • Secondary Zone Secondary Zone: This area is usually created on secondary servers. It is the same as the original area and has all the records in it, but with the difference that these records are not editable and in fact a read-only copy of the corresponding area.
  • Stub Zone Root Zone: Unlike two previous regions, this area does not store information from the records in the area, but only maintains the names of the names of the servers in the network that contain that area, and uses the open source method to analyze the name. The patrol uses the existing name servers.

Types of DNS Source Records

Each area has a number of resource records. For a computer, the most common source record is its IP address. But there are other types of source records. When a domain name is given to the DNS, all attribute references belonging to that area are returned. In fact, the main task of a DNS is to convert the region name into the resource records.

Each source record is composed of 5 parts. These records are often textual (a record is kept in each line, and the format is as follows: |

Domain_name Time_to_live Class Type Value

The Domain Name field is the domain name associated with this record. Usually, each area has a large number of records, and each database stores multiple areas. As a result, this field is the key to the search in the DNS database. The Time_ to_ live field specifies the duration of the record’s survival. For example, 3600 (number of seconds per hour). The value of the Class field for Internet information is always IN; for non-web-based information, other codes are also used. Type Type specifies the type of record.

  • Host (A): This type of record is commonly used for network objects such as computers, printers, etc. In this section, a full name and a 32-bit IP address are inserted and stored.
  • (Alias ​​(CNAME): This record is used to create a nickname for a client or server computer, for example, in a computer network called ServerL and the full name Server1. Network. Local is a web server that has access to This site is also available through the Internet.

Now, the network administrator to secure the site and stay the original host name of the Web server to prevent the possibility of hacking an Alias ​​record with the nickname www, and from now on, Internet users can use the 
Www.Network.Local address to this Have access to the site.

  • Start Of Authority (SOA): The DNS server that manages a specific domain is referred to as the domain SOA. Over time, search engine hosts in SOA will be published among other DNS servers and eventually become known throughout the Internet.
  • ointer (PTR): This type of record also refers to another name, like the CNAME. Unlike P CNAME, however, the PTR record is a typical DNS data type interpreted based on the contents of this record. In practice, this type of record is always used for reverse lookup, the “convert IP address to machine name”.
  • HINFO: This type of record returns information about the type and operating system of the car.
  • TXT: The TXT record is used to return additional text information to users.
  • (Mail Exchanger (MX): This record is used to address existing e-mail servers on the network (such as Exchange). This record is used for programs that need to communicate with these servers and send or receive For example, if someone wants to send email to user1 [at] microsoft.com, you must find the microsoft.com mail server address, which provides the MX record.

Below is a part of the DNS database in the cs area. vu nl is brought.

Authoritative data for cs.vu.nl;

cs.vu.nl. 86400 IN SOA Star Boss (9527,7200,7200,241920,86400)

cs.vu.nl. 86400 IN MX 1 zephyr

cs.vu.nl. 86400 IN NS star

top 86400 IN A

www 86400 IN CNAME star.cs.vu.nl



  • WOW! this is awesome and i think 99% of people have problem with DNS and meaning of the DNS. I am so happy to find this wonderful and technical article about DNS. I have one an issue about how to figure out in my network. I am look forward again for that in your website.

Leave a Reply

Your email address will not be published.