DNS Domain Name
The Domain Name System is the hierarchical naming system based on a distributed database of computers, services, or any resource connected to the Internet or a private network. Most importantly, it translates human-readable domain names into digital identifiers associated with networking equipment, allowing devices to be located and communicated worldwide. DNS is like a network’s “phonebook,” which is how the browser translates a domain name (for example, “facebook.com”) into the actual IP address of the server, which stores information requested by the browser.
How do DNS servers work
The DNS directory is distributed worldwide; it is stored in special servers called DNS servers (for example, “domain name servers”) that are interconnected and communicate regularly to synchronize directory information and create redundancy.
DNS servers and IP addresses
The DNS server stores specific information that associates the domain name with certain IP addresses. The domain may have one or hundreds of the IP addresses associated with it. The Amazon.com, for example, has thousands of servers worldwide, and the actual server a user connects to within one country is likely to be very different from another user elsewhere. Therefore, the global nature of Internet services requires distributed and scalable DNS servers to ensure that users can quickly search and resolve the desired server location wherever they are.
DNS lookup
The purpose of DNS is to translate the domain name into the appropriate IP address. This is also done by looking up the DNS records for the requested domain. There are usually eight steps in this DNS lookup process which follow the path of information from the original web browser to the DNS server and back again. DNS information is often cached in practice to reduce DNS lookup response time. When DNS information is not cached, the eight-step lookup process is as follows:
The eight steps in a DNS lookup:
- The user enters the domain name (e.g., facebook.com) into his browser, and the browser sends the query via his ISP to a DNS recursive resolver.
- The iterative DNS resolver, in turn, sends a query to the root DNS name server (.).
- The root server returns to the resolver the address of the top-level domain (i.e., “TLD”) the DNS root server, which contains the information required for the facebook.com domain. (Examples of the TLD top-level domain include “.com,” “.net,” and “.org,” where each TLD has its root DNS server.)
- In turn, the resolver sends the request for information to the TLD server (in this case, the TLD name server “.com”).
- The TLD name server also responds to the resolver with the target IP address of the domain name server.
- Next, the iterative DNS resolver sends the query to the domain’s DNS server.
- The DNS server of the domain returns the IP address to the DNS resolver of the requested domain (for example, “facebook.com.”
- Finally, the DNS resolver also returns the IP address of the requested domain to the requesting web browser. The browser sends an HTTPS request to the target IP address, and the server with that address returns the web page displayed in the user’s browser.
Types of DNS services
There are two basic types of services that DNS servers provide: Authorized DNS and the Recursive DNS. Both are the integral to the DNS infrastructure, but each serves the different purpose during a DNS query. The recursive DNS server is at the beginning, and the authoritative DNS server is at the end of the DNS query.
Recursive DNS Server: As discussed in the description of the DNS lookup process, a recursive DNS server responds to a request from the client and returns the IP address of the requested domain name. The iterative resolver server makes a series of recommendations until it reaches the authoritative DNS server for the requested domain.
Authorized DNS Server: The authoritative DNS server is the server that maintains and maintains the requested domain record. The trusted DNS server also has an updated mechanism, allowing administrators to manage their public DNS names. The authoritative DNS server is the ultimate source of truth for the domain’s DNS information. It is responsible for providing the domain’s IP address information back to the requested iterative DNS server.
