Part 1: The ARPANET Goes Postel
- The Domain Name System is a method by which "domain names" (e.g. berkeley.edu, ftp.xmission.com, well.com) can be resolved into IP addresses, which network applications need in order to perform network operations. This allows crl.com to resolve to 188.8.131.52, mx.org to resolve to 184.108.40.206, etc.
- Network namespace is organized into "domains"--little-endian, period-separated, hierarchically organized namespaces. E.g. the edu domain contains the berkeley.edu domain, which itself contains the sims.berkeley.edu domain, which "contains" hosts like www.sims.berkeley.edu (actually, in this case, www.sims.berkeley.edu is the same machine as sims .berkeley.edu, but either the way, the point is that both are "within" the sims.berkeley.edu domain).
- The basic idea of the modern DNS namespace was first articulated in RFC 920, by John Postel, aka IANA, the "ruler" of Internet numbering. This system implemented the .com (UC commercial), .org (US nonprofit organizations), .net (network providers from around the world), .mil (US military), .edu (US colleges/universities), and two-letter ISO country code domains for everyone else. There was little network use outside the US at the time, so the idea of pushing the "American" network domains under a .us hierarchy didn't seem very necessary, in what was then essentially a domestic network. It was explicitly left as a possibility that new top-level domains might be developed at some time in the future, without very much trouble. At this point in time, the Internet was largely used by functional academic, research, high-end technical, and government origanizations. As such, it was considered quite appropriate that all domain designations be functional in type.
- The domain name namespace as envisioned by Postel in RFC 920 grew and expanded. The .int domain was added for international organizations, but otherwise everything remained essentially static in terms of namespace expansion. Country-code TLDs started taking off around the world. Every nation came up with its own unique namespace-dividing system, from the "standard" identifier second level domains in the UK (.ac, .co, etc.) to the absolutely flat namespace of Germany (under the .de TLD). The US stuck out a bit because of its monopolization of the only "general" three-letter TLDs, but this issue was left alone.
- The .com domain was starting to "fill up" a bit by the early 1990s. There was some discussion of ways in which it could be revamped. Discussion of ways in which it could be placed under the .us domain was explicitly ended by Postel's RFC 1480.
- The status quo as of 1994, the year the Internet took off, was defined in RFC 1591. The .com, .org, and .net domains had been internationalized (i.e. no longer restricted for US institutions), and the .org domain was now opened up to all non-commercial organizations, not just registered nonprofits. The .com namespace was starting to grow at problematic rates. While there was some discussion going on about ways to flatten the .com namespace, no action was decided upon or taken.