How Domain Name Servers Work

In this post you’ve read about some important DNS basics. such as What is it, How it work, Why it is Important.

If you’ve ever used the Internet, it’s a good bet that you’ve used the Domain Name System, or DNS,  even without realizing it. DNS is a protocol within the set of standards for how computers exchange data  on the Internet and on many private networks, known as the TCP/IP protocol suite.

Without DNS servers, the Internet would shut down very quickly mean’s not work.

Baasic function/Job of DNS isTo resolve a Fully Qualified Domain Name(FQDN)/user-friendly domain name  into it’s corresponing IP (Internet Protocol) address.
e.g. :like “https://badrinathkadam.wordpress.com” into an IP address 72.233.2.58 that computers use to identify each other on the network.

Computers and other network devices on the Internet use an IP address to route your request to the site you’re trying  to reach. This is similar to dialing a phone number to connect to the person you’re trying to call. Thanks to DNS, though, you don’t have to keep your own address book of IP addresses. Instead, you just connect through  a domain name server, also called a DNS server or name server, which manages a massive database that maps domain names  to IP addresses.

Whether you’re accessing a Web site or sending e-mail, your computer uses a DNS server to look up the domain name you’re  trying to access. The proper term for this process is DNS name resolution, and you would say that the DNS server resolves the domain name to the IP address. For example, when you enter “https://badrinathkadam.wordpress.com” in your browser, part of  the network connection includes resolving the domain name “wordpress.com” into an IP address, like 72.233.2.58, for  wordpress Web servers.

You can always bypass a DNS lookup by entering 72.233.2.58 directly in your browser. However, you’re probably more likely to remember “wordpress.com” when you want to return later.
In addition, a Web site’s IP addresscan change over time, and some sites associate multiple IP addresses with a single domain name.

How does your computer know what DNS server to use?

 Typically, when you connect to your home network, Internet service provider (ISP) or WiFi network, the modem or router that assigns your computer’s network address also sends some important network configuration information to your computer or mobile device. That configuration includes one or more DNS servers that the device should use when translating DNS names to IP address.

What is DNS (Domain Name System) ?

 

Word definition/Function : The DNS translates Internet domain and host names to IP addresses. DNS automatically converts the names we type in our Web browser address bar to the IP addresses of Web servers hosting those sites.

Also known as Domain Name System, Domain Name Service, Domain Name Server.

DNS implements a distributed database to store this name and address information for all public hosts on the Internet.

Note : DNS  IP addresses do not change which are statically assigned rather than dynamically assigned.

Structure DNS of  Servers and Name Hierarchy :

The DNS database resides on a hierarchy of special database servers.The DNS maintains a distributed database of network names and addresses, and it provides methods for computers to remotely query the database.

Some people call DNS the “phone book of the Internet.”

DNS uses a client/server network architecture. DNS servers are the computers designated to store DNS database records (names and addresses), while clients of the DNS include PCs, phones and other devices of end users. DNS servers also interface with each other, acting as clients to each other when needed.

The DNS organizes its servers into a hierarchy. For the Internet, so-called root name servers reside at the top of the DNS hierarchy. The Internet root name servers manage DNS server information for the Web’s top-level domains (TLD) (like “.com” and “.uk”), specifically the names and IP addresses of the original (called authoritative) DNS servers responsible for answering queries about each TLD individually. Servers at the next lower level of the DNS hierarchy track second-level domain names and addresses (like “about.com”) , and additional levels manage Web domains (like “compnetworking.about.com”).

DNS servers are installed and maintained by private businesses and Internet governing bodies around the world. For the Internet, 13 root name servers (actually redundant pools of machines around the world) support the hundreds of Internet top-level domains, while About.com provides authoritative DNS server information for the sites within its network. Organizations can similarly deploy DNS on their private networks separately, on the smaller scale.

Working of DNS :

When clients like Web browsers issue requests involving Internet host names, a piece of software called the DNS resolver (usually built into the network operating system) first contacts a DNS server to determine the server’s IP address. If the DNS server does not contain the needed mapping, it will in turn forward the request to a different DNS server at the next higher level in the hierarchy. After potentially several forwarding and delegation messages are sent within the DNS hierarchy, the IP address for the given host eventually arrives at the resolver, that in turn completes the request over Internet Protocol.

All public Web sites run on servers connected to the Internet with public IP addresses.

The Internet utilizes DNS as a worldwide name resolution service for public Web sites. When someone types a site’s name into their browser, DNS looks up the corresponding IP address for that site, the data required to make the desired network connections between Web browsers and Web servers.

 for example : The Web servers at Badrinathkadam.com, have addresses like 207.241.148.80. Although people can type address information like ” http://207.241.148.80/”  into their Web browser to visit sites, being able to use proper names like ” http://www.badrinathkadam.com/ ”  is much more practical.

Alternatives to DNS : 

The Microsoft Windows Internet Naming Service (WINS) supports name resolution similar to DNS but works only on Windows computers and using a different name space. WINS is used on some private networks of Windows PCs.

I hope this is Helpful to all.