Proposed Telnet Changes
Arguments for keeping data type codes and password masking in Telnet.
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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§1Introduction
This RFC is a response to RFC 328, which proposed simplifying Telnet. Tom O'Sullivan agrees with the general direction but argues for keeping two features: Data Types and Hide Your Input (password masking). Removing these features would lose capabilities needed by specialized equipment and security-sensitive applications.
In Telnet discussions, someone suggested removing two optional features. This person says those two features are still useful.
§2Data Types
Data Types allow Telnet to switch out of ASCII mode to handle arbitrary 8-bit codes. This is essential for terminals with attached specialized equipment. Examples include Calcomp plotters, numerically controlled machines, and sensor experiments. Each non-ASCII mode should provide a return code to ASCII. Data Types serve real use cases on the ARPANET.
Some terminals have special gadgets plugged in (like a drawing machine or a drill controller) that use 8-bit codes the ASCII alphabet does not have. Telnet needs to handle this, and each gadget mode should have a way to get back to normal letters.
§3Hide Your Input
Hide Your Input (password masking) masks characters as they are entered, so passwords and access keys do not appear on the console. With more network database systems coming online and requiring passwords, this feature becomes more important, not less.
The concern that it is hard to select the masking length can be solved by letting the server program specify how many characters to mask, with a reasonable default. Passwords and secrets are critical to network security, so this feature should stay.
When you type a password, you want it hidden so nobody watching can see it. Network databases will need this more and more, so the feature is worth improving, not removing.