What is DNS?
DNS (Domain Name System) is a system of domain names, for obtaining, storing and updating information about domains.
DNS work is important, because it allows you to turn the alphabetic address of a site into its IP address.
A distributed DNS database is supported based on a specific protocol that is used by DNS servers.
The view of the hierarchical structure of a domain name is based on an understanding of how DNS servers interact with each other.
Any server that is responsible for the name has the right to delegate responsibility for a further part of the domain to another server. This allows you to assign responsibility for the relevance of information to the servers of different companies and organizations.
For example, the server responsible for the .com zone can delegate responsibility for the microsoft.com domain to another server.
Since 2010, the integrity of data transfer between DNS servers is verified by cryptographic methods, but the data itself is not encrypted, and is still transmitted in clear form.
Thus, DNS has the following characteristics:
- The distribution of administration, as the responsibility for different parts of the structure are different servers.
- Distribution of information storage, since DNS servers store only information that is in the zone of their responsibility. They can also store the addresses of the root DNS servers.
- Caching information, which manifests itself in the ability of the server to store information that is not within its area of responsibility. This is done to reduce the load on the network as a whole.
- A hierarchical structure in which the nodes of the network are united according to the topology of the "tree" and each node can independently determine the operation of the subordinate nodes.
- Redundancy, because for maintenance of nodes and storage of information, there are usually several different servers, separated on the physical and logical levels. This provides an opportunity to continue working and save data even during the failure of one of the nodes.