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
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.
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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 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].
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].
Generic security considerations for the usage of URIs are discussed in Section 7 of [RFC3986].
Yevstifeyev Standards Track [Page 3]
RFC 6270 The 'tn3270' URI Scheme June 2011
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].