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Tag Archive: DNS



In this post, I have came forward with the instructions and guidance to set the permanent hostname for the CentOS box.

Centos LogoIn this video, you find the needed configurations to setup the HOSTNAME.

The ip-address you see in the /etc/hosts file has been acquired from the concerned system, using the “ifconfig” command. The ipaddress is needed to mention the hostname in the hosts file. However you can find the ipaddress of your own computer using Ifconfig command in TUI (terminal) mode.

The setup has been chosen in the CentOS platform, as the demand is noticed in high. You can follow the same instruction for other Linux distributions, however the path, commands, Shell usage affects the process.

Here I have used “nano” as text editor to edit the configurations files, however you can use you favorite text editor; VI, CAT or other’s. After i have used the nano /etc/sysconfig/network   or other files editing, i have manipulated the files and i have saved the configurations using the CTRL+X  buttons click and pressing the Y button for the asked query, whether to save the changes or not by the nano editor; so i am saying yes to save the things. This will save the configured things.

you do need to exit the current working shell to notice the changes of hostname. However it is recommended to logout of the box after changes and login back again.  The next post about how to set-up DNS will be published soon.

Here in the video, the hostname has been mentioned as linuxbox1, and the fqdn has been assigned as the linuxbox.centos1; however it is recommended to use the linux box as the hostname or to change the fqdn to be as linuxbox1; both are acceptable.  (edited-16-06-10)

If you have any queries,  comment here or else you can reach me @ twitter.com/chaladhi     or   facebook.com/chaladi

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Today (31-May-2010), I am gonna write some needed info on DNS (Domain Name Service), which will be useful for Dummies or for  beginners of Linux.

Well, can I ask you the reason why your attention has been pulled up by Linux? Oh you could tell the same in comments section.

No more Scum, going straight into technology. I want the patience and of course Applause (Kidding!).

Linux gives you more flexibility and smooth life that you usually do need to sacrifice your lives on some machines. DNS is an essential thing, that should be deployed in the IT world for the humanity sake.!! Well DNS is the technology that performs Forward and reverse lookup operations. Oh I am going in-depth.. well let me be clear in my path, giving the definitions and words life.

Well, what’s your favorite web-site? Think of it! Oh-yeah, So every time you visit your favorite web-site by just entering the  website name in your favorite web browser (Soon the web browser section will be blogged down) and abracadabra – Your are there, watching your favorite site in the browser. Well actually, Just like as you have been named by your father & mother for the human race sake, every computer should be and will be named with unique name; that’s the IP address (Ex: 192.168.10.20: To see your own IP address; I mean your computer’s IP not your personal IP, as your Mom & Dad have already named you and with the gods grace you are Human not Freaking machine- Just Type “ifconfig” command in Linux boxes & in Windows, type “ipconfig”,  be sure to remove the quotations and to use just the rest letters. make sure you logged into your linux machine as root, not with your name or alternatives, ‘Cos the ifconfig won’t work on some machines in Linux distributions; I mean distributions are like Centos, Debian, Suse, Fedora etc.,).

So, morally, the computer machines in the whole world are assigned their names with unique numbers (Local and Internet participating computers have a controversial words now, with this statement). So, as of now, the said things on DNS is all about IP address and blah blah blah…… But that’s not a scum nor a spam to inject into your head. More to come, be patience.

As said, Each Computer will be assigned a IP address (numbers) and the computers identify them each other with the same (IP to IP). As the Humans couldn’t be able to memorize the numbers in hefty, the human intervention to make such serious situations smooth has been done. I mean, DNS has been deployed: The act of performing the name to IP address and Vice versa. this is just like as your favorite web-site name: for instance, Facebook.com is your favorite web-site, every time you visit the web-site with facebook.com typing in the browser address bar, Right! so in this case the Facebook.com is a Canonical name (alternative name) for the facebook.com computer. So the need to remember the IP address of 100’s of web sites is not needed; better that site names are easier to remember so. Isn’t it? That’s the same aspect of DNS innovated person.

So, It is the DNS that is making your life more comfort every time you visit the internet, else, I BET-YOU that the chances of visiting your favorite web-sites or being online will be drastically reduced, Isn’t it? Inevitably yes to say so. Hmm… Lemme grab a Cup of coffee for the survival.

(5 minutes later) Hmm.. that latte is much better, relaxing, moreish! So far I have been much into IP addresses, Hope, not you are bored yet! ☺♥♥♥. So DNS is comforting you from the corners of the IT technology to give you intense pleasure to enjoy the IT services. So, i hope you have investigated that, DNS is more important and vital for everyday life as well, for an IT person (Not Farmer nor a Plumber, as he is no way related or connected to IT services daily: Bet you Old ladies, you are on the list probably).

So, if you want to visit the facebook.com site, you can alternatively visit the site with the IP address as well: http://69.63.189.16/  …. This is what i am trying to tell you since from the beginning of the post…. Hope you got me at last…. So in this way, you can either use IP address or alternatively the Cnames (facebook).

In your Linux machines, the /etc/hosts file is more important and is vital for networking. The computer is said to see the local database (/etc/hosts) first and later the DNS servers for the query performing. If the local database /hosts file has the complete database of local computers IP address and their Cnames, the query needs no DNS server, else the need of DNS server is needed to resolve the names to IP address and IP to names. The settings to look firs the local database and later for the DNS server for resolutions are configured in /etc/nsswitch.conf file.

This post has been prepared to give you insights of the DNS technology, furthermore for the detailed info on DNS and setting up the DNS in Linux machines, please feel free to visit again for the information acquiring purposes. Soon the post with DNS installation on Linux distributions would be published.

If you have any comments to say so regarding the post or quality of the post, please comment or get me  in contact @ twitter.com/chaladhi

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