S.Kille@CS.UCL.AC.UK (Steve Kille) (07/26/89)
As everyone seemed to like the idea of factoring the UUCP quoting mechanism
out into a separate RFC, I've made a first cut. Comments please!
(Karen, could you put this into the internet drafts directory?)
thanks
Steve
Mailgroup Note nnn
UCL Research Note nnn
Network Working Group S.E. Kille
Request for Comments XXXX University College London
26th July 1989
Mapping between full RFC 822 and RFC 822 with
restricted encoding
Status of this Memo:
EDITOR'S NOTE: THIS IS DRAFT VERSION 1.0. THE INTERIM
NUMBER XXXX WILL BE REPLACED WHEN THIS DOCUMENT IS
FINALISED.
This RFC suggests a proposed protocol mapping for the ARPA-
Internet community and UK Academic Community, and requests
discussion and suggestions for improvements. Distribution
of this memo is unlimited.
This document describes a set of mappings which will enable
interworking between systems operating RFC 822 protocols in
a general manner, and those environments where transfer of
RFC 822 messages restricts the character set which can be
used in addresses. UUCP transfer of RFC 822 messages is an
important case of this[Crocker82a,Horton86a].
This document derives from a mapping originally specified in
RFC 987 [Kille86a], where the domain of application was more
restricted.
Kille [page 1]
RFC XXXX
Mapping between full and restricted RFC 822 DRAFT Version 1.0
Specification: This document specifies a mapping between two
protocols. This specification should be used when this
mapping is performed on the DARPA Internet or in the UK
Academic Community. This specification may be modified
in the light of implementation experience, but no
substantial changes are expected.
Kille [page 2]
RFC XXXX
Mapping between full and restricted RFC 822 DRAFT Version 1.0
1. Introduction
Some mail networks which use RFC 822 cannot support the full
character set required by all aspects of RFC 822. This document
describes a symmetrical mapping between full RFC 822 addressing,
and a form for use on these networks. Any addresses within the
networks will not use the full RFC 822 addressing, and so any
addresses encoded according to this standard will always
represent remote addresses.
This RFC describes a quoting mechanism which may be used to
allow general interworking between RFC 822, and variants of RFC
822 which do not support 822.quoted-string.
2. Encoding
Any EBNF definitions taken from RFC 822 are prefixed by the
string "822.".
The following EBNF is specified.
atom-encoded = *( a-char / a-encoded-char )
a-char = <any CHAR except specials (other than "@"
and "."), SPACE,
CTL, "_", and "#">
a-encoded-char = "_" ; (space)
/ "#u#" ; (_)
/ "#l#" ; <(>
/ "#r#" ; <)>
/ "#m#" ; (,)
/ "#c#" ; (:)
/ "#b#" ; (\)
/ "#h#" ; (#)
/ "#e#" ; ($=)
/ "#s#" ; ($/)
/ "#" 3DIGIT "#"
The 822.3DIGIT in EBNF.a-encoded-char must have range 0-127, and
is interpreted in decimal as the corresponding ASCII character.
The choice of special abbreviations (as opposed to decimal
encoding) provided is based on the manner in which this mapping
is most frequently used. There are special encodings for each of
the PrintableString characters not in EBNF.a-char, except ".".
Kille [page 3]
RFC XXXX
Mapping between full and restricted RFC 822 DRAFT Version 1.0
Space is given a single character encoding, due to its (expected)
frequency of use, and backslash as the RFC 822 single quote
character.
To encode (full RFC 822 -> restricted RFC 822), first remove
any quoting from any 822.quoted-string (typically in 822.local-
part). Then, all EBNF.a-char are used directly and all other
CHAR are encoded as EBNF.a-encoded-char.
To decode (restricted RFC 822 -> full RFC 822): if the
address can be parsed as EBNF.encoded-atom reverse the previous
mapping. If it cannot be so parsed, map the characters directly.
3. Application
This mapping should be used for all addresses, at the MTS or
Header level. For example:
Full RFC 822 Restricted RFC 822
Steve.Kille@cs.ucl.ac.uk <-> Steve.Kille@cs.ucl.ac.uk
"Steve Kille"@cs.ucl.ac.uk <-> Steve_Kille@cs.ucl.ac.uk
"argle#~"@blargle <-> argle#h##126#@blargle
References
Crocker82a.
D.H. Crocker, "Standard of the Format of ARPA Internet Text
Messages," RFC 822, August 1982.
Horton86a.
M.R. Horton, "UUCP Mail Interchange Format Standard," RFC
976, February 1986.
Kille86a.
S.E. Kille, "Mapping Between X.400 and RFC 822," UK Academic
Community Report (MG.19) / RFC 987, June 1986.
Kille [page 4]Stef@NRTC.NORTHROP.COM (Einar Stefferud) (07/26/89)
Good shot Steve -- I did howver have trouble trying to parse and understand one paragraph in particular, included next. > 1. Introduction > > Some mail networks which use RFC 822 cannot support the full > character set required by all aspects of RFC 822. This document > describes a symmetrical mapping between full RFC 822 addressing, > and a form for use on these networks. Any addresses within the > networks will not use the full RFC 822 addressing, and so any > addresses encoded according to this standard will always > represent remote addresses. I hesitate to attempt a rewrite it. I think my trouble stems from the use of too many pronouns and nonspecific references to vaugue or missing anticedents. Later on you formally speak of "Full RFC822" and "Restricted RFC822" in table headings. How about defining those terms a bit earlier and then using them to clarify the text. Best...\Stef