Domain Name System is a computing distributed technique designed to receive knowledge about domains and most commonly served for automatic receiving IP address by host name or managing message routing. DNS maintains hierarchical names systems identifying networking nodes and specified with RFC 1034 and 1035 standards. For the system realization special net protocol DNS was created alongside with appropriately designed information-retrieval or DNS servers.
All DNS network can be written in a form of a single hierarchical tree with a root domain on a top of it specified with “ “ symbol. Top-level domains are followed by domains of lower levels and up to hosts counted as leaf.
Example of DNS service functioning
Supposing a computer wants to know assigned IP number of the server with the following address: www.organization.sanfrancisco.us.
First of all, the device sends a request to its server which transmits necessary info or asks a root server if this information isn’t stored on its libraries. The L-root has no needed information, but it redirects a request to a DNS server responsible for “sanfrancisco” zone. In its turn, the request is reassigned to servers maintained “organization.sanfrancisco” zone.
Finally, the request comes to servers operated in “www.organization.sanfrancisco.us” zone which reply with necessary info.
This model is rather overdrawn, but DNS service can be briefly described in such a manner.
Frontmost DNS parameters
This System produces following information:
- host IP address;
- host domain name with its IP number;
- host alias, type of main unit and its operating system;
- network protocols supported with host;
- Mail gateway;
- mail box;
- mail group.
DNS key elements
The System has three major components:
- Names organization structure and associated info are determinate with domain names space and resources records. Each record involves specify info related to define name and describe source characteristics. What is concern information obtaining with request, user receives only its particular part. As an example, names are used with the Internet identifying hosts addresses and transforming in their IP locations at the request.
- Name servers process and manage info about subordinated domain name space and resources records.
- Resolves programs return knowledge stored in data base of domain names with customer request. Programs grant access at least to one title and use receiving information to generate an answer or forward a request to other naming server.
DNS features with following characteristics:
- Administration distribution described that different organizations assume responsibility for different elements of hierarchical structure.
- Data storage distribution divides information between network nodes responsible for holding accountable info.
- Several information can be stored with node reducing net capacity. This feature also known as data caching.
- Hierarchical structure supposing nodes cohesion in one single data tree where each part has control over operation of dependant nodes or delegates its duties to other nodes.
- Reservation means data protection and fault avoidance by dividing servers for storing and serving their nodes on physical and logical levels.