RFC 805 (rfc805) - Page 2 of 6


Computer mail meeting notes



Alternative Format: Original Text Document





Computer Mail Meeting Notes                              8 February 1982


   principle, be replaced by a "unique-id@location-id" model, where the
   unique-id would be a globally unique id for this mailbox (independent
   of location) and the location-id would be advice about where to find
   the mailbox.  However, it was recognized that the "user@host" model
   was well established and that so many different elaborations of the
   "user" field were already in use that there was no point in persuing
   this "unique-id" idea at this time.

   Several alternatives for the structuring and ordering of the
   extensions to the "host" field to make it into a general
   "location-id" were discussed.

      These basically involved adding more hierarchical name information
      either to the right or the left of the @, with the "higher order"
      portion rightmost or leftmost.  It was clear that the information
      content of all these syntactic alternatives was the same, so that
      the one causing least difficulty for existing systems should be
      chosen.  Hence it was decided to add all new information on the
      right of the @ sign, leaving the "user" field to the left
      completely to each system to determine (in particular to avoid the
      problem that some systems already use dot (.) internally as part
      of user names).

   The conclusion in this area was that the current "user@host" mailbox
   identifier should be extended to "ain" where "domain"
   could be a hierarchy of domains.

      In particular, the "host" field would become a "location" field
      and the structure would read (left to right) from the most
      specific to the most general.

         For example: "" might be the mailbox of Jon
         Postel on host F in the ISI complex of the Internet domain.

      Formally, in RFC 733, the host-indicator definition rule would
      become:

         host indicator = ( "at" / "@" ) domains

         domains = node / node "." domains

            Note only one "at" or "@" is allowed, and that the domains
            form a hierarchy with the most general in scope last.

            And note that the choice of domain names must be
            administratively controlled and the highest level domain
            names must be globally unique.




Postel