I know NAT was developed to solve the problem of IPv4 address exhaustion. I am not very familiar with the history of how the Internet evolved (except ARPAnet because that is in every networking book). I know the RFC for NAT was received in late 1990s.

So my question is, were the private IP ranges, as we know now used publicly before, and if yes, were the organizations using those forced to give up those IP addresses?

1 Answer 1


RFC 1631, The IP Network Address Translator (NAT) (May 1994, before the public Internet went commercial) defined NAT.

RFC 1918, Address Allocation for Private Internets (February 1996, after the public Internet went commercial) defined private addressing.

There was a law firm that was forced to surrender some addressing for the private address range.

  • Let me point out the private addressing was laid out first in RFC 1597 in March of 1994. You can also see that block was used by ARPANET if you look in any number of the historical RFCs, such as RFC 870.
    – YLearn
    Mar 2, 2018 at 3:21
  • Yes, but I took the meaning of "publicly" in the question to mean after the Internet went commercial. It is sort of gray area, and I nearly closed the questions as "historical trivia that does not allow for a concise and non-subjective answer or is trivial/irrelevant to modern networking," and I'm not fully convinced that it still shouldn't be.
    – Ron Maupin
    Mar 2, 2018 at 3:37

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