RFC 1026 (rfc1026) - Page 3 of 4

Addendum to RFC 987: (Mapping between X

RFC 1026                                                  September 1987


   To allow the mapping of null organisations to be represented in the
   specification of Appendix F, the dmn-orname syntax is extended, so
   that values may be given the symbol "@" (not a printable string
   character). This corresponds to an omitted attribute. The new
   definition is:

           dmn-orname      = dmn-part *( "." dmn-part )
           dmn-part        = attribute "$" value
           attribute       = standard-type
                           / "~" dmn-printablestring
           value           = dmn-printablestring
                           / "@"
           dmn-printablestring
                           = *( dmn-char / dmn-pair )
           dmn-char        = 
           dmn-pair        = "."

   Appendix F - Format of address mapping tables

   A new Appendix F is defined as follows:

   There is a need to specify the association between the domain and
   X.400 namespaces described in 4.2.1.  This is defined as a table
   syntax, but the syntax is defined in a manner which makes it suitable
   for use with domain nameservices (such as the Internet Domain
   nameservers or the UK NRS).  The mapping is not symmetric, and so a
   separate table is specified for each direction.  If multiple matches
   are possible, the longest possible match should be used.

   Various restrictions are placed on the usage of dmn-orname:

   1)   Only C, ADMD, PRMD, O, and OU may be used.

   2)   There must be a strict ordering of all components, with the most
        significant components on the RHS.

   3)   No components may be omitted from the hierarchy, although the
        hierarchy may terminate at any level.  If the mapping is to an
        omitted component, the "@" syntax is used.

   For domain -> X.400:

           domain-syntax "#" dmn-orname "#"

   Note that the trailing "#" is used for clarity, as the dmn-orname
   syntax can lead to values with trailing blanks.

           For example:

           AC.UK#PRMD$DES.ADMD$BT.C$UK#
           XEROX.COM#O$Xerox.ADMD$ATT.C$US#



Kille