DNS stands for Domain Name System, or Domain Name Server.
DNS resolves an IP address to a hostname or vice versa.
DNS is basically a large database which resides on various computers that contains the names and IP addresses of various hosts/domains. Other than ip-address DNS also associates various information with the domain names.
Structure of a DNSDNS uses a hierarchical tree based name structure. At top of the tree is the “root” ( represented as a dot (.) ) followed by the TLD ( Top Level Domain ), then by the domain-name and any number of lower level sob-domains separated by a dot.
The Top Level Domains are divided into 2 categories:
- 1. Generic TLD (gTLD)
- 2. Country Code TLD (ccTLD)
- .com – comercial web sites
- .org – non profit organizations web sites
- .edu – restricted to schools and institutions.
- .net – originally for network infrastructures, now unrestricted