Internet Engineering Task Force (IETF)                    M. Yevstifeyev
Request for Comments: 6270                                     June 2011
Updates: 1041, 1738, 2355
Category: Standards Track
ISSN: 2070-1721


                        The 'tn3270' URI Scheme

Abstract

   This document is the specification of the 'tn3270' Uniform Resource
   Identifier (URI) scheme, which is used to designate the access to the
   resources available via Telnet 3270 mode (TN3270) and Telnet 3270
   Enhanced mode (TN3270E).  It updates RFC 1041 and RFC 2355, which
   specify these protocols, and RFC 1738, which firstly mentioned this
   URI scheme without defining its syntax and semantics.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6270.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................2
      1.1. Terminology ................................................3
   2. URI Scheme Definition ...........................................3
      2.1. URI Scheme Syntax ..........................................3
      2.2. URI Scheme Semantics .......................................3
   3. Security Considerations .........................................3
   4. IANA Considerations .............................................4
   5. References ......................................................4
      5.1. Normative References .......................................4
      5.2. Informative References .....................................5
   Appendix A. Acknowledgments ........................................6

1.  Introduction

   This document specifies the 'tn3270' Uniform Resource Identifier
   (URI) scheme, which is used to designate the access to the resources
   available via Telnet 3270 mode (TN3270) and Telnet 3270 Enhanced mode
   (TN3270E).

   Telnet 3270 mode (TN3270) is a name used to denote the special mode
   of Telnet session [RFC0854].  If it is used, the 3270 data stream
   [GA23-0059] is used when transmitting data during the Telnet session,
   whereas the Telnet 3270 Regime option [RFC1041] is used to enable and
   negotiate its use.  (See [RFC1576] for some other background
   information on TN3270.)  Telnet 3270 Enhanced mode (TN3270E) has a
   similar principle; see RFC 2355 [RFC2355] for its specification.

   The 'tn3270' URI scheme was firstly mentioned in RFC 1738 [RFC1738]
   as used in URIs that designate the access to "Interactive 3270
   emulation sessions".  Following the creation of the URI schemes
   registry per RFC 4395 [RFC4395], this scheme was added to the
   "Provisional URI Schemes" sub-registry in the "Uniform Resource
   Identifier (URI) Schemes" IANA registry [URIREG].  However, RFC 1738
   [RFC1738] does not give any definition of syntax or semantics of the
   'tn3270' URIs and does not have any guidelines for registration of
   this scheme.

   Since there is no acceptable specification of the 'tn3270' URI, there
   is a risk that somebody might try to implement it with some new,
   possibly undocumented, syntax, just by looking at the IANA registry.
   In order to minimize such risk, this document gives a precise
   definition of syntax, semantics, use of this URI, and it registers
   the corresponding scheme.  It also updates RFC 2355 [RFC2355], RFC
   1738 [RFC1738], and RFC 1041 [RFC1041].

   The generic syntax of URIs is described in RFC 3986 [RFC3986].
   Registration procedures for new URI schemes are defined in RFC 4395
   [RFC4395].

1.1.  Terminology

   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 [RFC2119].

2.  URI Scheme Definition

2.1.  URI Scheme Syntax

   The 'tn3270' URI takes the following form (the syntax below is non-
   normative):

      tn3270://<userinfo>@<host>:<port>/

   where the <userinfo> part with the "@" (at) sign character, as well
   as the <port> part with the preceding ":" (colon) character, is
   OPTIONAL.

   The normative syntax of the 'tn3270' URI is defined in <tn3270-uri>
   ABNF [RFC5234] rule:

     tn3270-uri       = "tn3270:" "//" authority ["/"]

   where the <authority> rule is specified in RFC 3986 [RFC3986].

   The semantics of each part of the 'tn3270' URI are defined below, in
   Section 2.2.

2.2. URI Scheme Semantics

   The <host> part of the 'tn3270' URI, which is REQUIRED, denotes the
   host to which the TN3270 or TN3270E connection is to be established.
   The <userinfo> part is considered to define the information for use
   in the Telnet Authentication option [RFC2941], which might be used
   during the TN3270 or TN3270E session.  The <port> part, if present,
   denotes the port on which the TCP connection to the <host> is to be
   established.  If it is absent, the default port SHALL be 23, as
   registered in [PORTREG].

3.  Security Considerations

   Generic security considerations for the usage of URIs are discussed
   in Section 7 of [RFC3986].

   Since 'tn3270' URIs provide access to services that are available via
   TN3270 and TN3270E, which do not add any new security issues to the
   Telnet session, as they are a modified form of it, there are no other
   security considerations for 'tn3270' URIs that are not discussed in
   RFC 4248 [RFC4248], the 'telnet' URI scheme specification.

   The Telnet protocol, as well as TN3270 and TN3270E, is inherently
   insecure.  Those needing remote login access and related services are
   encouraged to use a more secure technology, such as Secure Shell
   [RFC4251].

4.  IANA Considerations

   IANA updated the registration of the 'tn3270' URI scheme using the
   following registration template (see [RFC4395]):

      URI scheme name: tn3270

      Status: Permanent

      URI scheme syntax: see Section 2.1 of RFC 6270

      URI scheme semantics: see Section 2.2 of RFC 6270

      URI scheme encoding considerations: there are no other encoding
      considerations for 'tn3270' URIs that are not described in RFC
      3986 [RFC3986]

      Protocols that use the scheme: Telnet 3270 mode (TN3270) [RFC1041]
      and Telnet 3270 Enhanced Mode (TN3270E) [RFC2355]

      Security considerations: see Section 3 of RFC 6270

      Contact: IESG <iesg@ietf.org>

      Author/Change controller: IETF <ietf@ietf.org>

      References: see Section 5 of RFC 6270

5.  References

5.1.  Normative References

   [RFC1041]   Rekhter, Y., "Telnet 3270 regime option", RFC 1041,
               January 1988.

   [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
               Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2355]   Kelly, B., "TN3270 Enhancements", RFC 2355, June 1998.

   [RFC3986]   Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
               Resource Identifier (URI): Generic Syntax", STD 66, RFC
               3986, January 2005.

   [RFC4248]   Hoffman, P., "The telnet URI Scheme", RFC 4248, October
               2005.

   [RFC5234]   Crocker, D., Ed., and P. Overell, "Augmented BNF for
               Syntax Specifications: ABNF", STD 68, RFC 5234, January
               2008.

5.2.  Informative References

   [GA23-0059] IBM Corporation, "IBM 3270 Information Display System.
               Data Stream Programmer's Reference", IBM Publication
               GA23-0059, July 1992.

   [PORTREG]   Internet Assigned Numbers Authority (IANA) Registry,
               "Port Numbers", <http://www.iana.org>.

   [RFC0854]   Postel, J. and J. Reynolds, "Telnet Protocol
               Specification", STD 8, RFC 854, May 1983.

   [RFC1576]   Penner, J., "TN3270 Current Practices", RFC 1576, January
               1994.

   [RFC1738]   Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
               Resource Locators (URL)", RFC 1738, December 1994.

   [RFC2941]   Ts'o, T., Ed., and J. Altman, "Telnet Authentication
               Option", RFC 2941, September 2000.

   [RFC4251]   Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
               Protocol Architecture", RFC 4251, January 2006.

   [RFC4395]   Hansen, T., Hardie, T., and L. Masinter, "Guidelines and
               Registration Procedures for New URI Schemes", BCP 35, RFC
               4395, February 2006.

   [URIREG]    Internet Assigned Numbers Authority (IANA) Registry,
               "Uniform Resource Identifier (URI) Schemes",
               <http://www.iana.org>.

Appendix A.  Acknowledgments

   Many thanks to Alfred Hoenes, Graham Klyne, Alexey Melnikov, Julian
   Reschke, and Peter Saint-Andre for their input to this document.

Author's Addresses

   Mykyta Yevstifeyev
   8 Kuzovkov St., flat 25,
   Kotovsk
   Ukraine

   EMail: evnikita2@gmail.com