What is DNS server? Types of name server? google DNS- by nearly tech

DNS[Domain Name System]

DNS Meaning

DNS is a part of Application Layer of the Internet Protocol Suite. DNS full form is domain name system or domain name server which is a server where IP address of particular domain is stored. Internet works with only IP address but humans can't remember IP address of each and every website we have to visit. So for that, a DNS server is made where we stored IP address of all domain name.

What is DNS server? Types of name server? google DNS- by nearlytech

Benefit

Domain name system which works on the DNS protocol is such that when we search for a domain name that request which is also called as DNS query is passed to DNS server where this server will find the IP which is associated with that domain name and returns that IP to our browser.

It's that simple...

This is how it benefits you...

• It will provide you with an IP address.
• It will store all IP address for all domain name.
• If DNS server doesn't know IP address then it will request for it to another DNS server.

So it is the time for you to lookup for detail DNS...

Preview

In this article, we will see the following points related to the domain name system or domain name server...

• DNS query
• Types of DNS server
• DNS lookup|DNS lookup tool
• How DNS works
• DNS caching
• Types of DNS query
• and many more...

 

DNS Query

DNS query is a process of sending a request for IP address which is related to that particular domain name. When we type a domain name in our browser then if a browser doesn't know the IP address. It will request to DNS server for an IP address. This request is called as DNS query.

Now here's the question that, Is there only one DNS request or only one DNS query???

and the answer is...

No, there are different types of query depending upon the request, those are as follows

1) Recursive Query

When a browser or a DNS recursive resolver made a request that query is called as a Recursive query. Generally, the basic request where the browser made with DNS recursive resolver is a recursive query. Other than that when DNS recursive resolver made a request with a root name server, authoritative name server, TLD name server these request are also called as Recursive Query.

2)Iterative Query

In the opposite way, if a browser or a DNS recursive resolver receives a request or in this case, we call it as they receive a suggestion from a root name server or from a TLD name server or an authoritative name server this is called as an Iterative query.

3)Non-recursive Query

Generally, if a query is placed to the DNS server and if DNS recursor server has access to that domain name then it will return it without processing the further request. 

let's see an example to understand non-recursive query...

If you and your friend want to search for www.nearlytech.com, If your friend searched that first and DNS server brought it's IP address for him/her by processing all simple steps and stored it in its catch memory. Then after that, if you made a search for www.nearlytech.com, the DNS server will not process all the steps which it did earlier and will provide you an IP address from its catch memory. 

These are the three simple types of DNS query.

image showing relation between browser and DNS server

How DNS Works

As we all know that DNS is a provider of IP address. If we give a domain name to it, then it will give us an IP address. Again for example if we want an IP address of domain www.nearlytech.com, and if we made a query to DNS. Then it will give us an IP of www.nearlytech.com, something like [191.245.46.73].

But to get the correct IP, DNS server follow some steps in it. When you enter any domain name in your browser and browser will send a query to DNS server there that query will pass through 5 simple steps. when you press domain name in your browser and press enter key immediately your page will start loading within a time of millisecond. But, DNS will perform 5 steps in less time in the backend.

Now before looking to the actual process of how DNS works, one should know some basic terminology or we can call it as steps of DNS system.

There is 5 DNS server involved in loading a webpage: 

1) Caching Name Server

2) DNS Recursor or DNS Recursive Resolver  

3) Root Name Server

4) TLD Name Server

5) Authoritative Name Server  

Before looking into how they perform their function we need what is their function and why we use them one by one...

1) Caching Name Server

Caching nameserver is nothing but our computer or browser. Sometimes DNS recursor is also called as caching name server. Caching nameserver contain cache memory which stores some most common IP address which is searched recently. 

We have seen an example of a non-recursive query that example is also an example of caching nameserver. In that example when the second user searches for www.nearlytech.com, then we have seen that DNS server directly give an iterative query to a computer.

that's okay...

but the question is that From where did DNS recursive resolver give an iterative query to computer or browser???😒😒😒

And the answer is simple,

The DNS recursive resolver stores that IP for that query in its cache memory. And whenever someone asks for that query, It will send an iterative query.

2)DNS recursor

Technically DNS recursor or DNS recursive resolver is the first server involved in loading web page. DNS recursor or DNS recursive resolver is also called as caching nameserver when it performs a caching action as we saw in above example. DNS recursor is also called as DNS recursive resolver because it resolves the communication between other three servers such as root nameserver, top-level domain(TLD) nameserver, authoritative nameserver.

DNS recursor communicate consecutively with other three servers. DNS recursor will first communicate with root name server. Asking for an IP address. Once if it gets an IP address it will pass an iterative query to a browser. And if not then it will ask for a path to find an IP address then root name server will provide an iterative query to it indicating which TLD server may have that IP address.

Similarly, it will communicate with other two name server until it gets an IP address. If DNS recursor did not find an IP address it will generate an error.

image showing how DNS works

3)Root Name Server

DNS root name server is the server which actually provides an IP address. When DNS recursive resolver does not have an IP address in its cache then it will pass that recursive query to root name server. Then root name server will give an IP address to DNS recursive resolver through an iterative query.

Then what if it does not contain an IP address???

Then, in this case, it will indicate DNS recursive resolver to communicate with TLD name server. In simple words, if DNS root name server does not contain an IP address then it will tell DNS recursive resolver to ask about the address to TLD name server. And will also provide information about the domain extension. For example, If DNS root name server does not know an IP address of www.nearlytech.com, then it will indicate DNS recursive resolver to go to TLD name server which has access to .com extension.

4)Top Level Domain [TLD] name server

Functioning of TLD name server is same as DNS root name server. It will communicate with DNS recursive resolver in the same manner as of DNS root name server communicate. But the only difference is that this DNS server works with domain extension. 

Let's see in above example...

If DNS recursive resolver sends a recursive query to TLD name server which has access with .com extension then that TLD name server gives an iterative query which contains an IP address. 

If TLD name server still does not know an IP address then it will indicate DNS recursive resolver towards Authoritative DNS name server.

5)Authoritative DNS name server

An authoritative DNS name server is the final stage of DNS name server. If DNS recursive resolver does not get an IP address from DNS root name server, DNS TLD name server, then it will send a recursive query to an authoritative name server.

An authoritative name server most probably contains an IP address. But if again it does not contain an IP address, It will ask for another DNS server or it will for Domain Name Registrar for that particular IP address.

Finally, we get our IP address for the connection 😔😔😒.

image showing steps of DNS

DNS Lookup or DNS Lookup Tool

DNS lookup is nothing but the complete process for understanding how DNS server work. DNS lookup is the step by step process about how DNS server works.

To understand DNS lookup the best way is an example. that's why let's look for www.nearlytech.com 

 DNS lookup is the process which includes following steps:

(1)When we type a domain name, for example, www.nearlytech.com then the browser will send a query by asking "what's the IP address associated with this domain name?" 

(2)This query will then pass to DNS recursive resolver or DNS recursor. Here if DNS recursor know its IP address it will send a non-recursive query to a browser. But if DNS recursor does not know an IP of www.nearlytech.com, then the recursive query will continue by passing it to DNS root name server.

(3) Here onwards same thing will continue with small changes. If DNS root name server knows an IP address of www.nearlytech.com, then it will send an iterative query to DNS recursor. or if root name server does not know an IP address of www.nearlytech.com, then it will give an indication to DNS recursor to go to which TLD name server.

(4) Once DNS recursor reach to TLD name server then TLD name server search it with its extension. Here, in this case, the extension is .com, TLD name server will provide its IP address, but if TLD name server still not got an IP address. Then it will indicate DNS recursor to go to an Authoritative name server.

(5) An authoritative name server is the final server list in loading our www.nearlytech.com, website. Similarly, if an authoritative name server knows an IP address then it will send an iterative query to DNS recursor. But if still, authoritative name server does not know an IP address for www.nearlytech.com, then it will ask domain name registrar for that IP. 

image showing steps of DNS with query

This is the complete process for how DNS server works. And this process is only called as DNS lookup.

Google DNS or Open DNS

Google DNS is nothing but the DNS server which is open for all to use. That's why sometimes is also called as Open DNS. Generally, we use DNS server which our ISP will provide, (Here ISP means internet service provider). But the problem with our ISP DNS server is that, the take time to update. 

It gets time to update means, for example, if an IP of a particular website gets changes. The server also needs to gets updated. That's why Google introduced google DNS server openly and which is also called as Google open DNS.

Google DNS is designed for better internet speed, to improve internet experience. Google DNS server is free DNS or public DNS. Google DNS IP is 8.8.8.8 or 8.8.4.4, these two are the IP address of Google DNS.  

So I think now you know about what is DNS, its types, its query, query types, about Google DNS, etc...

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