There are earlier references elsewhere, but the oldest Internet RFC I could find mention of it is RFC114 (Apr 1971), a Multics related doc called "A FILE TRANSF

There are earlier references elsewhere, but the oldest Internet RFC I could find mention of it is RFC114 (Apr 1971), a Multics related doc called "A FILE TRANSFER PROTOCOL" https://datatracker.ietf.org/doc/html/rfc114 https://datatracker.ietf.org/doc/html/rfc114 An excerpt: The cooperating processes may be "daemon" processes which "listen" to agreed-upon sockets, and follow the initial connection protocol much in the same way as a "logger" does. Related to MIT's "Project MAC", with the same Professor Fernando José Corbató involved as the Stack Exchange answer.