Is it possible that there is also a "future that stops using DNS"?The original role and evolution history of "DNS" leading from hosts.txt, the form of tomorrow

DNS that responds to the rapid spread of the Internet

　At the beginning, Mr. Yoshino, who was in charge of "DNS and the form of evolution at the time of birth", stated that when the Internet began, DNS was given priority and did not assume the existence of malicious intentions (Fig.1).

　The "Katachi", which does not assume the existence of malicious intentions, is that the Internet at the time has limited users and the purpose of use, and it is not anonymous, and the computing processing capacity and communication environment are so much.Considering the background that it was not good, it was unavoidable.At that time, the Internet was the highest priority to connect with the other party, and it was necessary to have a simple, light operation, and easy to implement and operate.

　The content shown in Fig. 1 is still often found in DNS commentary.Using UDP, one set of inquiries and answers by flat sentence, and 512 bytes of UDP message size will be familiar to those who have been involved in DNS for a long time (this figure will be later.It has a meaning, so please remember it).

　The original role of DNS is "name resolution", and by stringing the domain name and IP address, it is possible to communicate with the person you want to access by name.In other words, the Hosts can be used to use an easy -to -understand and easy -to -use "name" by replacing an IP address that is difficult to understand and hard to remember..This is the role of continuing from TXT.

　However, from the beginning, DNS assumed not only IP addresses corresponding to domain names but also more general information.A representative example of that was MX record, and it was possible to register the "server that should send e -mails to the domain name" as information.This function is the conventional Hosts.It was difficult to realize in TXT, and the spread of emails was one of the driving force to promote the spread of DNS (Fig. 2).

　Later, as the Internet became widespread, the addition of functions that were not enough for DNS, responding to new needs, and improving reliability and convenience (Figure 3).Examples of additional functions include IPv6 addresses and internationalization domain names, but in addition to the document, DNS Notify speeds up zone data synchronization between authority DNS servers, improving the efficiency of name resolution by negative cache, DNS other than Bind.It also describes the appearance of software implementation (Fig. 4).