RFC 1137 (rfc1137) - Page 2 of 3

Mapping between full RFC 822 and RFC 822 with restricted encoding

Alternative Format: Original Text Document
< Previous
Next >
RFC 1137           E-Mail Address and Quoted Strings       December 1989


   Restricted RFC 822

      This implies a subset of RFC 822 addressing.  The quoted-string
      form of local-part need not be supported.  Standard UUCP mail
      transfer falls into this category.  Restricted RFC 822 is
      undesirable, but in practice it exists in many places.

      When a message is transferred from full RFC 822 to restricted RFC
      822, and address forms used in full RFC 822 are involved, message
      loss may occur (e.g., it may not be possible to return an error
      message).  This RFC describes a quoting mechanism which may be
      used to map between full RFC 822 and restricted RFC 822, in order
      to alleviate this problem.

2.  Encoding

   The RFC 822 EBNF meta notation is used.  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          = 
      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 ".".  Space is
   given a single character encoding, due to its (expected) frequency of
   use, and backslash as the RFC 822 single quote character.

   This mapping is used to transform between the two forms of 822.word:
   822.quoted-string (restricted RFC 822) and 822.atom (restricted RFC



Kille
< Previous
Next >