TELNET KERMIT OPTION
RFC 2840
Document | Type |
RFC - Informational
(May 2000; No errata)
Was draft-altman-telnet-kermit-server (individual)
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Authors | Jeffrey Altman , Frank Cruz | ||
Last updated | 2013-03-02 | ||
Stream | Legacy | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 2840 (Informational) | |
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group J. Altman Request for Comments: 2840 F. da Cruz Category: Informational Columbia University May 2000 TELNET KERMIT OPTION Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119. ABSTRACT This document describes an extension to the Telnet protocol to allow the negotiation, coordination, and use of the Kermit file transfer and management protocol over an existing Telnet protocol connection. CONTENTS 1. MOTIVATION . . . . . . . . . . . . . . . . . . . . . . . . 2 2. DEFINITIONS. . . . . . . . . . . . . . . . . . . . . . . . 2 3. COMMANDS AND CODES . . . . . . . . . . . . . . . . . . . . 3 4. COMMAND MEANINGS . . . . . . . . . . . . . . . . . . . . . 3 5. KERMIT PROTOCOL IMPLICATIONS . . . . . . . . . . . . . . . 5 6. EXAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.1. EXAMPLE 1. . . . . . . . . . . . . . . . . . . . . . . . 6 6.2. EXAMPLE 2. . . . . . . . . . . . . . . . . . . . . . . . 7 6.3. EXAMPLE 3. . . . . . . . . . . . . . . . . . . . . . . . 8 6.4. EXAMPLE 4. . . . . . . . . . . . . . . . . . . . . . . . 9 6.5. EXAMPLE 5. . . . . . . . . . . . . . . . . . . . . . . . 10 7. SECURITY CONSIDERATIONS. . . . . . . . . . . . . . . . . . 11 8. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . 11 9. AUTHORS' ADDRESSES . . . . . . . . . . . . . . . . . . . . 11 10. FULL COPYRIGHT STATEMENT. . . . . . . . . . . . . . . . . 12 Altman & da Cruz Informational [Page 1] RFC 2840 TELNET KERMIT OPTION May 2000 1. MOTIVATION The Kermit protocol [KER] performs error-corrected file transfer and management over many types of connections, including terminal connections, among diverse hardware and software platforms. It is supported by a large number of Telnet clients and is also widely available on the Internet hosts to which Telnet connections are made. Traditionally, the Kermit protocol connection is started manually by a user, or perhaps by an automated script. It is the user's responsibility to start the Kermit server on one end of the connection and the Kermit client on the other, or to start a Kermit "send" operation on one end and a Kermit "receive" on the other. This procedure grew out of necessity on ordinary direct-dial connections, and serves its purpose within the limitations of that context. But it introduces timing and dexterity problems, and lacks an effective way for each Kermit program to determine the "mode" of the other, or even its very presence, and therefore to know with certainty which operations and procedures are legal on the connection at any given time. When Kermit services are offered on the Internet, however, a strong coupling can be established between the two end applications by having the Telnet protocol [TEL] serve as a supervisor for Kermit sessions, ensuring that a valid and known relationship is always obtained. Kermit sessions are, in effect, embedded within Telnet sessions, with Telnet providing the mechanism for starting and stopping them and defining which end is the Kermit client and which is the Kermit server, possibly changing the relationship in response to user actions. 2. DEFINITIONS Kermit server A software program that is ready to accept and act upon commands in the form of well-defined Kermit packets [KER]. Kermit client A software program that receives requests through its user interface from a human agent (or a script or other source) and translates them to command packets, which it sends to a Kermit server, thus initiating a Kermit protocol transaction such as the transfer of one or more files. Altman & da Cruz Informational [Page 2] RFC 2840 TELNET KERMIT OPTION May 2000 Availability of Kermit server For the purposes of this document, a Kermit server is said to be available if, through the negotiations described herein, its Telnet partner knows that it is a Kermit server. 3. COMMANDS AND CODES Support for a Kermit server is negotiated separately in each direction, allowing Kermit service to be embedded in the Telnet client, the Telnet server, or in both. The proposed TelnetShow full document text