Proposed Telnet Changes
Why Telnet should keep data types and input hiding
O'Sullivan, T.C., "Proposed Telnet Changes", RFC 340, DOI 10.17487/RFC0340, May 1972, <https://www.rfc-editor.org/info/rfc340>.
@misc{rfc340,
series = {Request for Comments},
number = 340,
howpublished = {RFC 340},
publisher = {RFC Editor},
doi = {10.17487/RFC0340},
url = {https://www.rfc-editor.org/info/rfc340},
author = {T.C. O'Sullivan},
title = {{Proposed Telnet Changes}},
pagetotal = 2,
year = 1972,
month = may,
} RFC text
Network Working Group Tom O'Sullivan Request for Comments: 340 Raytheon Company NIC 9933 Sudbury, Mass. Categories: Telnet References: RFC 328 15 May 1972 PROPOSED TELNET CHANGES The proposed change to the TELNET protocol calling for one standard protocol and dropping the idea of minimum implementation seems reasonable at this time. I suggest that both Data Types and Hide Your Input be kept for the following reasons: Data Types: The objection stating that switching out of ASCII results in an irreversible change and loss of control can be met by requiring other codes to provide to a return to ASCII. Each other code may have its own return code, however, it may not always be employed. Other codes are important for alphanumeric terminals that have special devices attached. Several potential cases can be cited: 1. Cal comp plotter attached to a teletype has logic permitting a program to turn the plotter on and off. When operating I believe it uses an 8 bit code which could conflict with Telnet signals. 2. Numerically controlled machines, either controlled from a user terminal or code prepared by a HOST computer to be punched on the paper tape punch at a teletype way require the use of an arbitrary 8 bit code. 3. Experiments controlled from alphanumeric terminal or sensor data collected through a cal-comp like connection may require the use of a full 8 bit code. In these cases a transparent data type with a provision for a return to ASCII mode seems desirable. Hide Your Input: As more and more use of data base systems in the network is considered, the need for and importance of using access keys, passwords, etc. grows. The fact that it is difficult to select the length of input to be hidden is not a persuasive argument. Potential solutions seem to exist, e.g. the protocol could provide for accepting length statements from the user program, data base system, operating system, etc. and in default of this, use a default length representing the server system expected optimum length. [ This RFC was put into machine readable form for entry ] [ into the online RFC archives by BBN Corp. under the ] [ direction of Alex McKenzie. 12/96 ]
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§1The Proposed Telnet Changes
Tom O'Sullivan responds to proposed changes to Telnet. He considers it reasonable to use one standard protocol rather than a minimum implementation, but recommends retaining Data Types and Hide Your Input.
The rest of the note gives reasons for retaining these two functions.
The author supports one standard Telnet protocol. He also argues that two features should remain available to users.
§2Support for Non-ASCII Data
Data Types would let a connection use codes other than ASCII. The author gives examples of equipment that may need arbitrary 8-bit codes: a plotter attached to a teletype, numerically controlled machines and experiments that collect sensor data.
He says each alternate code should provide a way to return to ASCII, though the return code need not be identical for every code.
Some attached devices use codes that are not ASCII. The author wants Telnet to carry those codes and provide a way to return to ASCII.
§3Hiding Access Keys and Passwords
Hide Your Input lets a program prevent typed characters from appearing on the user's screen. O'Sullivan says this is important as network database systems use access keys and passwords. He suggests that a program could specify how many characters to hide, with a default length when no length is supplied.
A user may need to type a password without showing it on the screen. The author suggests letting a program specify how many characters to hide.