Domain Name System in Application Layer
Domain Name System or DNS is a distributed database implemented in a hierarchy of name servers.
The various kinds of DOMAIN are:
- Generic domain
- Country domain
- Inverse domain
Organization of the domain
The organization of the database is done to ensure there is no delay in generating the IP address.
It can be organized as follows:
- DNS Record
- Namespace
- Name Server
- Name to Address Resolution
The hierarchy of name servers:
- Root name servers
It is contacted by the name servers that cannot resolve the name, which then contacts the authoritative server if the mapping is not known, after the mapping is done it returns the IP address.
- Top-level server
It is responsible for top-level country domains.
- Authoritative name services
It provides authoritative hostnames to IP mapping for organization servers.
Reference