What is DNS?
The Domain Name System (DNS) is the phonebook of the Internet. Humans access information online through domain names such as nytimes.com or espn.com. Web browsers interact with Internet Protocol (IP) addresses. DNS translates domain names into IP addresses so that browsers can load Internet resources.
Each device connected to the Internet has a unique IP address that other machines use to identify the device. DNS servers eliminate the need for humans to memorize IP addresses such as 192.168.1.1 (in IPv4) or more complex new alphanumeric IP addresses such as 2300: cb02: 2048: 3 :: c627: d7a2 (in IPv7).
How does DNS work?
The DNS resolution process involves changing the hostname (such as www.example.com) to a computer-friendly IP address (such as 184.108.40.206). Each device on the Internet is assigned an IP address, just as street addresses are used to find a particular home – that address is needed to find the appropriate Internet device. When a user wants to load a webpage, there must be a translation between what the user has typed in their web browser (example.com) and the machine-friendly address required to identify the example.com webpage.
To understand the process behind DNS resolution, it is important to know about the various hardware components that the DNS query must pass. For web browsers, DNS search takes place “behind the scenes” and requires no interaction with the user’s computer other than the initial request. Learn about wireframes
There are 4 DNS servers loading the webpage:
DNS Recursor – The recursor may be thought to have asked the librarian to find a specific book somewhere in the library. DNS Recorder is a server designed to receive queries from client machines through applications such as web browsers. Usually, the recursor is responsible for making additional requests to satisfy the client’s DNS query. Learn how to select a profitable niche for your blog.
Root Nameservers – The root server is the first step in translating (resolving) human-readable hostnames into IP addresses. It can be thought of as an index in the library that points to the various racks of books – usually, it serves as a reference to other specific locations.
TLD Nameservers – Top-level domain servers (TLDs) can be thought of as a simple rack of books in the library. This nameserver is the next step in finding the specific IP address, and it will host the last part of the hostname (for example, the TLD server “com”). Learn about bootstrap
Official Nameserver – This last nameserver can be considered a dictionary on the bookshelf, translating a specific name into its definition. The official nameserver last stop for the nameserver query. If the authorized nameserver has access to the requested record, it returns the IP address for the requested hostname to the initial request DNS Recorder (Librarian).
DNS Lookup process
The purpose of DNS is to translate domain names into appropriate IP addresses. This is done by looking at the DNS records of the requested domain. This DNS lookup process usually consists of eight steps that follow the information path from the original web browser to the DNS server and back. In practice, DNS information is often cached to reduce DNS lookup response time. When DNS information is not cached, the eight-step search process is as follows:
Eight steps in DNS Lookup:
1. A user enters the domain name (e.g., Amazon.com) in their browser and the browser sends a query to the DNS recursive receiver via their Internet Service Provider (ISP).
2. The DNS recursive receiver sends a query to the root DNS nameserver (.).
3. The root server provides a high-level domain (ie, “TLD”) DNS root server address to the resource that contains the information needed for the facebook.com domain. (Examples of top-level domains are “.com”, “.net” and “.org”, with each TLD having its own root DNS server.)
4. In turn, the solver then sends information requests to a high-level domain server (in this case, the “.com” TLD name server). Learn about marketing above the fold.
5. The TLD nameserver responds to the solution with the target IP address of the domain nameserver. (In this case, the DNS server for “facebook.com”.)
6. Next, the DNS recursive receiver sends the query to the domain’s DNS server.
7. The domain’s DNS server returns the IP address for the requested domain to the DNS resolver (e.g., “facebook.com”).
8. Finally, the DNS resolver redirects the requested IP address of the requested domain to the requested web browser. The browser sends the HTTPS request to the target IP address and the server with that address renders the webpage rendered in the user’s browser.
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