DNS stands for Domain Name System. The DNS system was invented by Paul Mockapetris in 1983. Before the DNS system was invented, there was a single file called hosts.txt in every computer which needed to be updated manually every time there was a change in the computer network called ARPANET at the time.

Protocol and Format DNS Messages The DNS protocol uses a common message format for all exchanges between client and server or between servers. The DNS messages are encapsulated over UDP or TCP using the "well-known port number" 53. DNS uses UDP for message smaller than 512 bytes (common requests and responses). All dns_sd constants (supported by the implementation) are exposed on the mdns object. Refer to the dns_sd API documentation for a list. mdns.isAvahi. A boolean that is true when running on avahi. It’s a kludge though. mdns.dns_sd. mdns.dns_sd contains the native functions and data structures. The functions are bound to javascript using the “If you use a hostname in the host portion of IPv4/v6 socket address, the program may show a non-deterministic behavior, as Python uses the first address returned from the DNS resolution. The socket address will be resolved differently into an actual IPv4/v6 address, depending on the results from DNS resolution and/or the host configuration. The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. HTTP has been in use by the World-Wide Web global information initiative since 1990. The first version of HTTP, referred to as HTTP/0.9, was a simple protocol for raw data transfer across the Internet.

DNS Transport Protocol. DNS uses the User Datagram Protocol (UDP) on port 53 to serve DNS queries. UDP is preferred because it is fast and has low overhead. A DNS query is a single UDP request from the DNS client followed by a single UDP reply from the server.

This tutorial will provide system administrators an understanding of the DNS protocol, including advanced topics such as DNSSEC (DNS Security). It will provide practical information about configuring DNS services using examples from the popular ISC BIND DNS software platform. Topics include: the DNS protocol and how it works, DNS

The Domain Name System also specifies the technical functionality of the database service that is at its core. It defines the DNS protocol, a detailed specification of the data structures and data communication exchanges used in the DNS, as part of the Internet Protocol Suite.

DNS is a distributed database that contains mappings of DNS domain names to data. It is also a protocol for Transmission Control Protocol/Internet Protocol (TCP/IP) networks, defined by the Requests for Comments (RFCs) that pertain to DNS.