DNS ServerSUBRATA PAULROLL NO: 13015411COMPUTER SCIENCE & ENGINEERING

Question: What Is a DNS Server?

 The Domain Name System is a standard technology for managing public names of Web sites and other Internet domains.

DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4.

Now the question is How DNS server works?

When we visit a domain such as dyn.com, our computer follows a series of steps to turn the human-readable web address into a machine-readable IP address.

Step 1: Request information The process begins when we ask our computer to resolve a hostname, such as visiting http://dyn.com. The first place our computer looks is its local DNS cache which stores information that our computer has recently retrieved.

Step 2: Ask the recursive DNS serversIf the information is not stored locally, our computer queries (contacts) our ISP’s recursive DNS servers. Recursive servers have their own cachesStep 3: Ask the root nameserversIf the recursive servers don’t have the answer, they query the root nameservers. They don’t know the answer, but they can direct our query to someone that knows where to find it.

Step 4: Ask the TLD nameserversThe root nameservers will look at the first part of our request, reading from right to left — www.dyn.com — and direct our query to the Top-Level Domain (TLD) nameservers for .com. Each TLD, such as .com, .org, and .us, have their own set of nameservers, which act like a receptionist for each TLD. Step 5: Ask the authoritative DNS serversThe TLD nameservers review the next part of our request — www.dyn.com — and direct our query to the nameservers responsible for this specific domain.

Step 6: Retrieve the recordThe recursive server retrieves the A record for dyn.com from the authoritative nameservers and stores the record in its local cache.Step 7: Receive the answerOur computer stores the record in its cache, reads the IP address from the record, then passes this information to our browser. This entire process, from start to finish, takes only milliseconds to complete.

DNS root structure

Why we use DNS server?

We can think of DNS as being like a phone book. Those people we want to call frequently, we usually either know their numbers or have their numbers on speed dial/saved on our cells/etc. But sometimes we need to call someone that isn't in our speed dial or memory. That is where the Domain Name System comes in. When we, for example, type in google.com into our web browser, our service provider sends that address to a (usually our ISP's) DNS server, which then looks at the info "google.com" sent to it, looks it up and says, "it's IP address is 74.125.45.100," and sends that info back to your home computer. Your computer then knows where to find the Internet resource.

Benefits of DNS Server1.Capable of providing security.

2.Errors are automatically checked.

3.Ease of using.

4.Flexibility of use.

5.Consistent to use.

6.Easy to maintain.

7.No need to memorise numbers.

8.Domain names makes / gives a kind of sense to hyper links when a name is given instead of a string of numbers .

Problems we face by using DNS server

Breakdown of DNS would crash the world wide web though there are many root servers and backup servers targetting DNS servers at particular key locations would do lot of harm

Price of Domain and hosting in Bangladesh

But the price can be vary with the business issue and the location where we are using

References: 1.http://arfitech.com/cheap_domain_registration_bangladesh.php

https://technet.microsoft.com

2.https://www.google.com.bd/search?q=tree+structure+of+dns+server&biw=1137&bih=607&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjN0eHwoMfJAhUDV44KHSW9BpkQsAQIMA#imgrc=TDV_6oTjca3HkM%3A

3.www.wikipedia.com

Thank You