The File Transfer Protocol (RFC0172)
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2019-Feb-10
Internet Society Requests For Comment (RFCs)
A. Bhushan: AUTHOR [+9]
Network Working Group 23 June 1971 Request for Comments #172 Abhay Bhushan, MIT NIC 6794 Bob Braden, UCLA Categories: D.4, D.5, and D.7 Will Crowther, BBN Updates: 114 Eric Harslem, Rand Obsolete: None John Heafner, Rand Alex McKenzie, BBN John Melvin, SRI Bob Sundberg, Harvard Dick Watson, SRI Jim White, UCSB
THE FILE TRANSFER PROTOCOL
The file transfer protocol (FTP) is a user-level protocol for file transfer between host computers (including terminal IMP’s), on the ARPA computer network. The primary function of FTP is to facilitate transfer of files between hosts, and to allow convenient use of storage and file handling capabilities of other hosts. FTP uses the data transfer protocol described in RFC 171 to achieve transfer of data. This paper assumes knowledge of RFC 171.
The objectives of FTP are to promote sharing of files (computer programs and/or data), encourage indirect use (without login or implicit) of computers, and shield the user from variations in file and storage systems of different hosts, to the extent it is practical. These objectives are achieved by specifying a standard file transfer socket and initial connection protocol for indirect use, and using standard conventions for file transfer and related operations.
A file is considered here to be an ordered set of arbitrary length, consisting of computer (including instructions) data. Files are uniquely identified in a system by their pathnames. A pathname is (loosely) defined to be the data string which must be input to the file system by a network user in order to identify a file. Pathname usually contains device and/or directory names, and file names in case of named files. FTP specifications provide standard file system commands, but do not provide standard naming convention at this time. Each user must follow the naming convention of the file system he wishes to use. FTP may be extended later to include standard conventions for pathname structures.
A file may or may not have access controls associated with it. The access controls designate the users’ access privilege. In the absence of access controls, the files cannot be protected from accidental or unauthorized usage. It is the prerogative of a resident file system to provide protection, and selective access. FTP only provides identifier and password mechanisms for exchange of access control information. It should however be noted, that for file sharing, it is necessary that a user be allowed (subject to access controls) to access files not created by him.
FTP does not restrict the nature of information in the file. For example, a file could contain ASCII text, binary data computer program, or any other information. A provision for indicating data structure (type and byte size) exists in FTP to aid in parsing, interpretation, reconfiguration, and storage of data. To facilitate indirect usage, the cooperating file transfer processes may be disowned "daemon" process...