Re: TELNET question
Theodore Ts'o <tytso@mit.edu> Fri, 18 November 1994 19:03 UTC
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From: Theodore Ts'o <tytso@mit.edu>
Message-Id: <9411181839.AA13932@dcl.MIT.EDU>
To: lee@huachuca-jitcosi.army.mil
Cc: billw@cisco.com, iptp@huachuca-jitcosi.army.mil, telnet-ietf@cray.com
In-Reply-To: Lee Chastain's message of Thu, 17 Nov 94 09:38:47 MST, <9411171638.AA04606@huachuca-jitcosi.army.mil>
Subject: Re: TELNET question
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Date: Thu, 17 Nov 94 09:38:47 MST From: lee@huachuca-jitcosi.army.mil (Lee Chastain) In the current (newline) test I assume no negotiation was done so that it wouldn't interfere with the testing of the default conditions. Given that the server/tester was wrong to send just the LF, wasn't the user implementation also wrong to process it as a newline rather than just a 'plain' LF ? As far as the telnet protocol is concerned, yes, an implementation that processes an LF as a "move carriage to the left hand margin and scroll the network virtual terminal up one line" is in violation of the telnet specification. Certainly if the implementation is doing even when connecting to port 23, and acting as a telnet client, then it's doing something wrong. The question boils down to this: Is a TELNET user only a proper implementation of TELNET when the server port is 23? ^^^^ You mean "client" where you wrote "user", right? That's really the crux of the matter. The RFC's document the telnet *protocol*. The question is when is the client obligated to follow the telnet protocol, and when is it not so obligated? The consequences are as follows: 1. No - TELNET is TELNET regardless of the server port : Then any implementation which defaults to LF as a newline (such as unix-based hosts) is not conformant to the TELNET standard. (Possible interoperability problems). 2. Yes - TELNET is only TELNET when the server port is 23: Not only did the tester send the wrong character(s), but its testing methodology is seriously flawed; the use of the non-standard port means that it is not truly testing TELNET, whether it had sent the correct newline code or not. Give that the IANA has specified that the port for telnet service is 23, I would tend towards option 2. The fair way to test things is on the original port. I think it is a "local matter" what the telnet client does going to other ports. Ideally, there should be a switch that indicates where or not the client should be initiating the options negotiations. How that switch is offered ought to be presented to the user is a UI issue, and not one that should be addressed in a protocol specification. (And, indeed, there is such a switch on the Berkeley reference implementation; you simply prefix the port number that you specify with a '-' character.) - Ted
- TELNET question Lee Chastain
- Re: TELNET question William Chops Westfield
- Re: TELNET question Theodore Ts'o
- Re: TELNET question Lee Chastain
- Re: TELNET question Philippe-Andre Prindeville
- Re: TELNET question William Chops Westfield
- Re: TELNET question Theodore Ts'o
- Re: TELNET question braden
- Re: TELNET question Theodore Ts'o