What does a DNS server actually do?

So what is a DNS server?

Well, DNS is expanded to Domain Name System. It’s a protocol or, a set of rules to keep the address of various websites in one place. Allow me to explain further. When we enter the name of a website, i.e. Perform a page request look up, we actually enter something like http://www.google.comor http://www.Facebook.com in the URL. However Machines being the way they are cannot handle names, rather they work in numbers. So each and every website has an Internet Protocol or I.P address assigned to it. An IP address is a   number separated by four periods. For example 192.168.0.5 . In order to co-relate between names of various websites and their IP address, a common medium is required which will play the part of a translator, much like a middle man who helps in a conversation between people speaking two different languages. So, A DNS server is the solution, which keeps track of various names of various websites and their corresponding IP address.

So how does it actually work?

When we request a webpage like http://www.google.com, a query is forwarded to our Internet Service Provider, where server performs a DNS Lookup. What it actually does is that it tries to find if the server contains the requested query and if it does, it tries to match it with it corresponding IP address. If it finds a positive match, it returns back the IP address. This process is called Resolving.
Now what if the DNS server of our ISP does not contain the IP address of the website we are looking for?
If this be the case, the query is forwarded to another DNS server, belonging to another ISP. If the problem still persists, the query is again forwarded to another DNS server until the IP address of the requested webpage is found. There are a multiple DNS server in existence which might contain the same data, hence If a DNS server is down, another server makes sure that the IP address of the requested webpage is always resolved.
So, whenever we enter the address of a webpage, it’s a two-step process.

  •  The address is fed into a DNS server, which returns a number i.e. the I.P address of the computer.
  •  The IP address is fed into the browser which downloads the requested page.
Does it mean we can omit the first step?
Sure we can, it makes the work easier on the part of the computer. However this is practically not realised because of the following reasons.
·         A computer is fast. It takes about a microsecond to perform a DNS look up. So it doesn’t really save our time.
·         We visit about hundreds of webpages every month. It would be foolish and impossible to remember an exhaustible list of websites and their corresponding IP address.

So how can we manually enter the IP address of a website?

Well its quite simple. Follow the instructions given below:
1.       Hold down the start button of your keyboard simultaneously with R.
The run window opens up.
2.       Type in “cmd” (without quotes) and press enter.
A command shell prompt will open up.
3.       Now in the command shell type:
ping [name_of_the_webpage]
4.       A statement will appear like the following:
Pinging [a_number] with 32 bytes of data.
5.       The IP address of the requested web page is the number received in place of [a_number].
Example:
Pinging http://www.i.google.com[74.125.236.146] with 32 bytes of data
Hence the required IP address is 74.125.236.146
If we enter this number in the URL feed, the localised homepage of Google will open up.
During a DNS look up, the DNS server of our ISP is selected by default. If it fails to resolve a website, we can always use a public DNS server.
So, how do we choose a public DNS server?
There are many public DNS servers available. We will choose Google’s public DNS server.
The addresses of Google’s public DNS servers are 8.8.8.8 and 8.8.4.4
Follow the steps given below to change your default DNS server into Google’s public DNS server:
(You must keep the internet connection active)
·         Go to Control-panel and choose Network and Internet.
·         From the new window that appears, select Network and Sharing Center.
·         Under control panel home, click on change adapter settings.
·         On, the next window that appears, Right-Click on the active connection(It is marked by the green circle with a tick mark inside it),and choose properties.
·         A dialogue box opens up. Under the Networking sub tab, double click on the Internet Protocol Version 4(TCP/IPv4) button.
·         Now, Click on the Use the following DNS server address radio button
and put the following data as shown below:
Preferred DNS server     8.8.8.8
Alternate DNS server     8.8.4.4
Then click on OK.
·         Restart the connection.

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