
AWS Certified Advanced Networking – Specialty (ANS-C01) Certification Guide
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The predecessor of the modern internet was the U.S. Department of Defense Advanced Research Projects Agency (DARPA) funded experimental wide area network called ARPAnet. ARPAnet came online on October 29, 1969, with 4 test sites and was decommissioned on Feb 28, 1990. Its purpose was to allow government contractors to share expensive computing resources.
Very early on, it was recognized that having a directory of hostnames to network address mappings made the network more usable. Stanford Research Institute maintained a text file called HOSTS.TXT
containing all the ARPAnet addresses to name mappings.
By the early 1980s, ARPAnet had grown to the point that a simple text file was no longer feasible, which resulted in RFC 882 and RFC 883, the initial RFCs for DNS.