Overview about DNS

Shikhar Verma • 30,000+ Students Worldwide
A free video tutorial from Shikhar Verma • 30,000+ Students Worldwide
Professional system administrator and IT Trainer
4.3 instructor rating • 25 courses • 34,316 students

Lecture description

Please find the attached ppt for the course section DNS (Domain name system) and use it for your reference and please don't share it with anyone.

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30:31:26 of on-demand video • Updated February 2021

  • Linux Administration with Troubleshooting Skills
  • Linux basic concepts,Introduction & History of Unix/Linux
  • Linux Interview Questions and Answers
  • Bash profile, Variables & Standard Input output Redirecting
  • Linux User Administration
  • Permissions in Red Hat Linux
  • Controlling Access to files with ACLs
  • Process Management
  • Kernel Modules
  • Disk Partitions, File Systems Creations & RAID Configuration
  • Logical Volume Manager Administration
  • RPM (Red Hat Package Manager)
  • YUM (Yellowdog Updater, Modified)
  • Linux OS Minor Upgrade
  • FTP - File Transfer Protocol
  • Apache Web Server Administration
  • DNS (Domain Name System)
  • Samba Server Concepts & Configuration
  • Network File System  (NFS)
  • Automating Installation using kickstart
  • Networking Concepts in Linux
  • Linux Performance Monitoring
  • Troubleshooting Linux Boot Problems in Linux (Basic System Recovery)
  • Overview of Red Hat Enterprise Linux 7
  • GRand Unified BootLoader (Grub2)
  • Kdump configuration on RHEL 7
  • Overview of Red Hat Satellite 6.2
  • Managing SELinux Security
  • Backup and Restore
  • Linux Commands Tutorials
  • Advanced Linux Commands
  • Linux Crontab
  • OpenSSH
  • Postfix Mail Server Configuration
English [Auto] Hello everyone. Let's continue. I understand about a very important topic that is domain name system that is DNS which works on port number 53. So DNS is basically it is an Internet service that controls domain name into their corresponding IP address and Weiss Warsaw. This is a simple definition of a DNS or in other words if you want to explain DNS that is it resolves the query of the client's in any organization. We have seen that that is a great rule of DNS. Let me try to explain the functionality of a DNS with an example. Suppose you know I have an organization and it in my organization a lot of servers are there. I'm just taking an example of internet where I do not have my domain is not connected with the outside world. It's only internet right. So I have a domain. Suppose the domain which I have that example dot com and in my domain there are a lot of so us like your web so our application server database so backup so application. So you know different different servers I have in my organization 50 or 60 so was I have a lot of you know clients they're sitting on different different servers and they want to communicate to each other so that all of DNS is that it resolves the query of the claims. So what is the query. Suppose there is one server like your web server and somebody is sitting on that server and they want to communicate to some other so well that is an application server. So what will happen we all know that the communication will always happen at the network layer and they need the IP address of the destination. So. So the client and when we want to open or when we want to communicate to any other so well we need an IP address and usually we always prefer to write the name of someone like Google dot com like yahoo dot com. If anybody is going to ask you what is IP of Google obviously we are not aware of that. So who is you know helping us to provide the IP to solve the destination servers. So here what happened. The plane was sitting on any of the servers and if they want to communicate to some other servers so they will take and help from the DNS server in the DNS servers they have the information of all the servers whatever present in your organization. Suppose I have 40 servers so all the 40 servers with their name and IP they are present on the DNS servers and all the flying machines all the servers. They have the information about the DNS server so all the information which I need to put in my all the servers that is then formation of the DNS servers. So whenever you know I want to communicate to some other service what will happen I will immediately asked to my DNS servers. I have a contribution file that is it is all dot com in that file. We are maintaining the name of your DNS server. So we lost to the DNS server like I want to communicate to the servers. So what will happen that DNS will respond back to you like this is an IP of the destination so that you want to communicate a query. And with that IP the user will be able to communicate. So this is you know the simple words of definition. That is it is all the credit of the clients. So let's understand with that now. Any computer on the Internet can maintain a file that usually associates IP address with domain name. So what happened you know when we do not have the DNS. So at that time you know the people the sys admin they are maintaining a file that is EDC host file in that file. You know we are maintaining the information of all the servers that that is present in the environment with the name and IP. So you know in my domain I have 50 servers of 40 so us. So on all the servers we have to maintain a file that is EDC host file and in that file we are keeping the information of all the servers like their name and IP. So whenever they want to communicate to any of the servers they always prefer that file to get the IP address of that specific server. And this exercise you have to do it on all the servers. So these are wanted was that somebody you know if you're going to add a new server in your environment so what will happen you have to do the same exercise again on all the cells you have to edit that it is your host file on all the servers and you have to put the new Silver entry also because you know you are going to you know change an IP address of any specific server. So what will happen. You have to you know change the IP address from all the servers. It is you host file. So to overcome this problem. They have introduced the concept of DNS. So now instead of you know editing all ladies it just fine. We have one dedicated servers in my organization and in that. So as we have putting all the service IP so all the clients all the servers whatever they are present in my organizations whenever they need any IP or any name of the servers they will simply ask for the dinner service. Nice. The DNS servers responsibility to resolve the query. Right. So using this method how would e computer needs a complete listing of all other computers on the nature of this listing must be updated constantly. So they are talking about that it is supposed to file the DNS have been implemented to deal with the task of translating the domain name of any computer on the Internet to its IP address. So as of now you know we have understand the concept of DNS and that is basically for the internet where we do not have the internet my domain is not connected with the Internet. So here what will happen. We have only one server. That is my DNS servers and all the clients will start creating. Right. So suppose you know in my my domain is connected with the internet then what is the functionality of your dean is how the Dean is willing I'll take the help from other attractive servers. So this is what we will understand in the next lecture. So from there so far of this lecture hope you have got a concept conceptual idea of DNS. So we have a lot of more things to understand in DNS. So thanks for watching and if you have time please join with me the next lecture.