History Flashcards
When was DNS invented?
In 1982. before 1982, each computer on the network retrieved a file called HOSTS.TXT from a computer at SRI. The HOSTS.TXT file mapped names to numerical addresses and host file still exists today on most modern operation systems.
What is BIND?
In 1984, four Berkeley students, wrote the first Unix name server implementation, called The Berkeley Internet Name Domain (BIND) Server.
What is a domain name?
A domain name consists of one or more parts, technically called labels, that are conventionally concatenated, and delimited by dots, such as example.com.
What are the parts of a domain name?
The right-most label conveys the top-level domain; for example, the domain name www.example.com belongs to the top-level domain com.
What is a domain name space?
Domain name space consists of a tree of domain names. Each node or leaf in the tree has zero or more resource records, which hold information associated with the domain name. The hierarchy of domains descends from right to left; each label to the left specifies a subdivision, or subdomain of the domain to the right. For example: the label example specifies a subdomain of the com domain, and www is a sub domain of example.com. This tree of subdivisions may have up to 127 levels.
What is a zone?
The tree sub-divides into zones beginning at the root zone. A DNS zone may consist of only one domain, or may consist of many domains and sub-domains, depending on the administrative authority delegated to the manager.
How many levels of subdivision can a tree have?
A tree may have up to 127 levels of subdivisions.
How many characters can a label have?
A label can have up to 63 characters.
How many characters can an external full domain name have?
The full domain name may not exceed a total length of 253 characters in its external dotted-label specification.
