DNS: the internet's phone book

In the early ARPANET, turning a host name into an address meant looking it up in one table, HOSTS.TXT, kept on a single host and copied by everyone else. Every new machine meant editing the master file and waiting for the rest of the network to fetch the new version.

That works for a few hundred machines. It does not work for millions. In 1983 Paul Mockapetris, at the University of Southern California's Information Sciences Institute, designed a replacement: a distributed, dynamic naming system. He published it that November as RFC 882 and RFC 883.

Your computer still has a hosts file, by the way. It is checked before DNS, which is why malware likes to edit it.