One document matched: draft-ietf-fax-minaddr-v2-02.txt
Differences from draft-ietf-fax-minaddr-v2-01.txt
Network Working C. Allocchio
Group GARR-Italy
INTERNET-DRAFT September 2000
Obsoletes: RFC2303 Expires: March 2001
Updates: RFC2846 File: draft-ietf-fax-minaddr-v2-02.txt
Minimal GSTN address format in Internet Mail
Status of this Memo
This document is an Internet Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-Drafts.
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reference material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
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Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
Abstract
This memo describes a simple method of encoding GSTN addresses
(commonly called "telephone numbers") in the local-part of Internet
email addresses, along with an extension mechanism to allow encoding
of additional standard attributes needed for email gateways to
GSTN-based services.
As with all Internet mail addresses, the left-hand-side (local-part)
of an address generated according to this specification, is not to be
interpreted except by an MTA that handles messages for the domain given
in the right-hand-side.
1. Introduction
Since the very first e-mail to GSTN services gateway appeared, a
number of different methods to specify a GSTN address as an e-mail
address have been used by implementors. Several objectives for this
methods have been identified, like to enable an e-mail user to access
GSTN services from his/her e-mail interface, to allow some kind of
"GSTN over e-mail service" transport (possibly reducing the costs of
GSTN long distance transmissions) while using the existing e-mail
infrastructure.
This memo describes the MINIMAL addressing method to encode GSTN
addresses into e-mail addresses and the standard extension mechanism
to allow definition of further standard elements. The opposite
problem, i.e. to allow a traditional numeric-only GSTN device user to
access the e-mail transport service, is not discussed here.
This IANA registration templates which MUST be used to register any
standard element defined according to this specification are given in
the "IANA Considerations" chapter (section 7 of this document).
All implementations supporting this GSTN over e-mail service MUST
support as a minimum the specification described in this document.
The generic complex case of converting the whole GSTN addressing into
e-mail is out of scope in this minimal specification: there is some
work in progress in the field, where also a number of optional
standard extensions are being defined.
1.1 Terminology and Syntax conventions
In this document the formal definitions are described using ABNF
syntax, as defined into [7]. This memo also uses some of the "CORE
DEFINITIONS" defined in "APPENDIX A - CORE" of that document. The
exact meaning of the capitalised words
"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", "OPTIONAL"
is defined in reference [6].
In this document the following new terms are also defined:
I-pstn device:
a device which has an Internet domain name and it is able to
communicate either directly or indirectly with the GSTN network;
mta-I-pstn:
the Internet domain name which identifies uniquely an I-pstn
device over the Internet;
pstn-email:
the complete Internet e-mail address structure which is used to
transport a GSTN address over the Internet e-mail service.
2. Minimal GSTN address
The minimal specification of a GSTN address within an e-mail address is
as follows:
pstn-address = pstn-mbox [ qualif-type1 ]
pstn-mbox = service-selector "=" global-phone
service-selector = 1*( DIGIT / ALPHA / "-" )
; note that SP (space) is not allowed in
; service-selector.
; service-selector MUST be handled as a case
; INSENSITIVE string by implementations.
Other specifications adopting the "pstn-address" definition MUST define
and register with IANA a unique case insensitive "service-selector"
element to identify the specific messaging service involved.
These specifications and registrations MUST also define which minimal
"qualif-type1" extensions, if any, MUST be supported for the specified
messanging service.
Implementations confirming to this minimal requirements specification
are allowed to ignore any other non-minimal extensions address element
which is present in the "pstn-address". However, conforming
implementations MUST preserve all "qualif-type1" address elements
they receive.
The generic "qualif-type1" element is defined as:
qualif-type1 = "/" keyword "=" string
keyword = 1*( DIGIT / ALPHA / "-" )
; note that SP (space) is not allowed in keyword
string = PCHAR
; note that printable characters are %x20-7E
As such, all "pstn-address" extension elements MUST be defined in
the "qualif-type1" form at the time of registration with IANA.
2.1 Minimal "global-phone" definition
The purpouse of global-phone element is to represent standard E.164
numeric addresses [10] within a syntax for electronic mail addressing
that is compliant with standard e-mail specifications given in [1]
and [2].
The minimal supported syntax for global-phone element is as follows:
global-phone = "+" 1*( DIGIT / written-sep )
written-sep = ( "-" / "." )
The use of other dialling schemes for GSTN numbers (like private
numbering plans or local dialling conventions) is also allowed.
However, this does not preclude nor remove the mandatory requirement
for support to the "global-phone" syntax within minimal GSTN address
format.
Any other dialling schemes MUST NOT use the leading "+" defined here
between the "=" sign and the dialling string. The "+" sign is
strictly reserved for the standard "global-phone" syntax.
Note:
The specification of alternate dialling schemas is out of scope
for this minimal specification.
This document also permit the use of written-sep elements in order to
improve human readibility of GSTN e-mail addreses. The written-sep are
elements which can be placed between dial elements such as digits
etc.
Implementors' note:
Use of the written-sep elements is allowed, but not recommended
for transmission. Any occurences of written-sep elements in a
pstn-mbox MUST be ignored by all conformant implementations. User
Agents SHOULD remove written-sep elements before submitting messages
to the Message Transport System.
2.2 The minimal "pstn-address" examples
Some examples of minimal pstn-address follows:
VOICE=+3940226338
FAX=+12027653000/T33S=6377
SMS=+33-1-88335215
Note:
only the use of registered service-selector and qualif-type1
elements is allowed. The examples shown are just for illustration
purposes.
3. The e-mail address of the I-pstn device: mta-I-pstn
An "I-pstn device" has, among its characteristics, a unique
Internet domain name which identifies it on the Internet. Within
Internet mail, this is the Right Hand Side (RHS) part of the
address, i.e. the part on the right of the "@" sign. For purpouses
of this document we will call this "mta-I-pstn"
mta-I-pstn = domain
For "domain" strings used in SMTP transmissions, the string MUST
conform to the requirements of that standard's <domain>
specifications [1], [3]. For "domain" strings used in message
content headers, the string MUST conform to the requirements of the
relevant standards [2], [3].
Note: both in the SMTP envelope and in the message headers, the
standards permit the use of "domain names" or "domain literals"
in addresses.
4. The pstn-email
The complete structure used to transfer a minimal GSTN address over
the Internet e-mail transport system is called "pstn-email". This
object is a an e-mail address which conforms to [2] and [3]
"addr-spec" syntax, with structure refinements which allows the
GSTN number to be identified.
pstn-email = ["/"] pstn-address ["/"] "@" mta-I-pstn
Implementors' note:
The optional "/" characters can result from translations from
other transport gateways (such as some X.400 gateways) which
have included the "/" as an optional element. Implementations
MUST accept the optional slashes but SHOULD NOT generate them.
Gateways are allowed to strip them off when converting to
Internet mail addressing. Implementors are reminded that it is
essential that "pstn-address" element MUST strictly follow the
"quoting rules" spcified in the relevant standards [2], [3].
4.1 Multiple subaddresses
There are some instances in GSTN applications where multiple
subaddresses are used. On the other hand in e-mail practice
a separate and unique e-mail address is always used for each
recipient.
In the event a particular GSTN service requires multiple
subaddresses (in any form defined by the standard specification for
that GSTN service) that are associated with the same "pstn-mbox",
then the use of multiple "pstn-email" elements is REQUIRED.
Implementors' note:
The UA may accept multiple subaddress elements for the same
global-phone, but it MUST generate multiple "pstn-mbox" elements
when submitting the message to the MTA.
4.2 Some examples of minimal "pstn-email" addresses
Some examples of minimal pstn-email addresses follows:
VOICE=+3940226338@worldvoice.com
FAX=+1.202.7653000/T33S=6377@faxserv.org
/SMS=+33-1-88335215/@telecom.com
Note:
only the use of registered service-selector and qualif-type1
elements is allowed. The examples shown are just for illustration
purpouses.
5. Conclusions
This proposal creates a minimal standard encoding for GSTN addresses
within the global e-mail transport system. It also defines the
standard extension mechanism to be used to introduce new elements for
GSTN addresses.
The proposal is consistent with existing e-mail standards. Each
specific GSTN service using this proposal MUST define and register
with IANA its own "service-selector" specification and MUST define
and register the eventual other "qualif-type1" elements needed for
its specifical application. An example of such an application is
contained in reference [13].
6. Security Considerations
This document specifies a means by which GSTN addresses can be
encoded into e-mail addresses. Since e-mail routing is determined by
Domain Name System (DNS) data, a successful attack to DNS could
disseminate tampered information, which causes e-mail messages to be
diverted via some MTA or Gateway where the security of the software
has been comprimised.
There are several means by which an attacker might be able to deliver
incorrect mail routing information to a client. These include: (a)
compromise of a DNS server, (b) generating a counterfeit response to
a client's DNS query, (c) returning incorrect "additional
information" in response to an unrelated query. Clients SHOULD ensure
that mail routing is based only on authoritative answers. Once DNS
Security mechanisms [5] become more widely deployed, clients SHOULD
employ those mechanisms to verify the authenticity and integrity of
mail routing records.
7. IANA Considerations
As the service-selector and qualif-type1 elements values are
extensible ones, they MUST be registered with IANA.
To register a service-selector or a qualif-type1 element, the
registration form templates given in 7.1 and 7.2 MUST be used.
Any new registration MUST fulfil the "Specification Required"
criterium, as defined in RFC 2434, section 2 [16]:
"Specification Required - Values and their meaning MUST be
documented in an RFC or other permanent and readily available
reference, in sufficient detail so that interoperability
between independent implementations is possible."
IANA MUST NOT accept registrations which are not supplemented by
a Specification as defined above and which are not fully specified
accoding to the template forms given in 7.1 and 7.2. In case of need
for further consultation about accepting a new registration, IANA
SHOULD refer to the Application Area Director to be directed to the
appropriate "expert" individal or IETF Working Group.
After succesful registration, IANA should publish the registered new
element in the appropriate on-line IANA WEB site, and include it
into the updates of the "Assigned Numbers" RFC series.
This section (including 7.1 and 7.2) updates the ones contained in
[15].
7.1: IANA Registration form template for new values of GSTN
address service-selector
To: IANA@isi.edu
Subject: Registration of new values for the GSTN address
service-selector specifier "foo"
service-selector name:
foo
Description of Use:
foo - ("foo" is a fictional new service-selector used in this
template as an example, it is to be replaced with the new value
being registered. Include a short description of the use of the
new value here. This MUST include reference to Standard Track RFCs
and eventaully to other Standard Bodies documents for the complete
description; the use of the value must be defined completely
enough for independent implementation).
Security Considerations:
(Any additional security considerations that may be introduced by
use of the new service-selector parameter should be defined here or
in the reference Standards Track RFCs)
Person & email address to contact for further information:
(fill in contact information)
INFORMATION TO THE SUBMITTER:
The accepted registrations will be listed in the "Assigned Numbers"
series of RFCs. The information in the registration form is freely
distributable.
7.2: IANA Registration form template for new values of GSTN
address qualif-type1 keyword and value
To: IANA@isi.edu
Subject: Registration of new values for the GSTN address
qualif-type1 element "bar"
qualif-type1 "keyword" name:
bar
qualif-type1 "value" ABNF definition:
abnf - ("abnf" MUST define the ABNF form of the qualif-type1 value.
The ABNF specification MUST be self-contained, using as basic
elements the tokens given in specification [4]. To avoid any
duplication (when appropriate), it MUST also use any already
registered non-basic token from other qualif-type1 elements,
i.e. it MUST use the same non-basic token name and then repeat its
identical ABNF definition from basic tokens.
Description of Use:
bar - ("bar" is a fictional description for a new qualif-type1
element used in this template as an example. It is to be replaced
by the real description of qualif-type1 element being registered.
Include a short description of the use of the new qualif-type1 here.
This MUST include reference to Standards Track RFCs and eventually
to other Standard Bodies documents for the complete description; the
use of the value MUST be defined completely enough for independent
implementation.)
Use Restriction:
(If the new qualif-type1 elements is meaningful only for a specific
set of service-element, you MUST specify here the list of allowed
service-element types. If there is no restriction, then specify the
keyword "none")
Security Considerations:
(Any additional security considerations that may be introduced by
use of the new service-selector parameter should be defined here or
in the reference Standards Track RFCs)
Person & email address to contact for further information:
(fill in contact information)
INFORMATION TO THE SUBMITTER:
The accepted registrations will be listed in the "Assigned Numbers"
series of RFCs. The information in the registration form is freely
distributable.
8. Author's Address
Claudio Allocchio
INFN-GARR
c/o Sincrotrone Trieste
SS 14 Km 163.5 Basovizza
I 34012 Trieste
Italy
RFC822: Claudio.Allocchio@elettra.trieste.it
X.400: C=it;A=garr;P=Trieste;O=Elettra;
S=Allocchio;G=Claudio;
Phone: +39 040 3758523
Fax: +39 040 3758565
9. References
[1] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
August 1982. --> DRUMS?
[2] Crocker, D., " Standard for the format of ARPA Internet text
messages", STD 11, RFC 822, August 1982. --> DRUMS?
[3] Braden, R., "Requirements for Internet hosts - application and
support", RFC 1123, October 1989.
[4] Malamud, C. and M. Rose, "Principles of Operation for the
TPC.INT Subdomain: Remote Printing -- Technical Procedures", RFC
1528, October 1993.
[5] Eastlake, D. and C. Kaufman, "Domain Name System Security
Extensions", RFC 2065, January 1997.
[6] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119, March 1997.
[7] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications", RFC 2234, November 1997.
[8] ITU F.401 - Message Handling Services: Naming and Addressing for
Public Message Handling Service; recommendation F.401 (August
1992)
[9] ITU F.423 - Message Handling Services: Intercommunication
Between the Interpersonal Messaging Service and the Telefax
Service; recommendation F.423 (August 1992)
[10] ITU E.164 - The International Public Telecommunication Numbering
Plan E.164/I.331 (May 1997)
[11] ITU T.33 - Facsimile routing utilizing the subaddress;
recommendation T.33 (July, 1996)
[12] ETSI I-ETS 300,380 - Universal Personal Telecommunication
(UPT): Access Devices Dual Tone Multi Frequency (DTMF) sender
for acoustical coupling to the microphone of a handset telephone
(March 1995)
[13] Allocchio, C., "Minimal FAX address format in Internet Mail",
RFC 2304 bis, xxxxx 1999.
[14] Kille, S., "MIXER (Mime Internet X.400 Enhanced Relay): Mapping
between X.400 and RFC 822/MIME", RFC 2156, January 1998.
[15] Allocchio, C. "GSTN address element extensions in e-mail
services", RFC 2846, June 2000.
[16] Narten, T., Alvestrand, H., "Guidelines for Writing an IANA
Considerations Section in RFCs", RFC 2434, October 1998.
10. Full Copyright Statement
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
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