RFC 2919 (rfc2919) - Page 2 of 9

List-Id: A Structured Field and Namespace for the Identification of Mailing Lists

RFC 2919                        List-Id                       March 2001


   proposals like [RFC 2369] have expanded the functionality that the MUA
   can provide by providing more information in each message sent by the
   mailing list distribution software.

   Actually implementing such functionality in the MUA depends on the
   ability to accurately identify messages as belonging to a particular
   mailing list.  The problem then becomes what attribute or property to
   use to identify a mailing list.  The most likely candidate is the
   submission address of the mailing list itself.  Unfortunately, when
   the list server host, the list processing software, or the submission
   policy of the list changes the submission address itself can change.
   This causes great difficulty for automated processing and filtering.

   In order to further automate (and make more accurate) the processing
   a software agent can do, there needs to be some unique identifier to
   use as an identifier for the mailing list.  This identifier can be
   simply used for string matching in a filter, or it can be used in
   more sophisticated systems to uniquely identify messages as belonging
   to a particular mailing list independent of the particular host
   delivering the actual messages.  This identifier can also act as a
   key into a database of mailing lists.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.

2. The List Identifier Syntax

   The list identifier will, in most cases, appear like a host name in a
   domain of the list owner.  In other words, the domain name system is
   used to delegate namespace authority for list identifiers just as it
   has been used to distribute that authority for other internet
   resources.

   Using the domain name system as a basis for the list identifier
   namespace is intended to leverage an existing authority structure
   into a new area of application.  By using the domain name system to
   delegate list identifier namespace authority, it becomes instantly
   clear who has the right to create a particular list identifier, and
   separates the list identifier from any particular delivery host or
   mechanism.  Only the rights-holder of a domain or subdomain has the
   authority to create list identifiers in the namespace of that domain.
   For example, only the rights-holder to the "acm.org" domain has the
   authority to create list identifiers in "acm.org" domain.







Chandhok & Wenger           Standards Track