List-Id: A Structured Field and Namespace for the Identification of Mailing Lists (RFC2919)

Network Working Group R. Chandhok Request for Comments: 2919 G. Wenger Category: Standards Track QUALCOMM, Inc. March 2001

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

Status of this Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2001). All Rights Reserved.

Abstract

Software that handles electronic mailing list messages (servers and user agents) needs a way to reliably identify messages that belong to a particular mailing list. With the advent of list management headers, it has become even more important to provide a unique identifier for a mailing list regardless of the particular host that serves as the list processor at any given time.

The List-Id header provides a standard location for such an identifier. In addition, a namespace for list identifiers based on fully qualified domain names is described. This namespace is intended to guarantee uniqueness for list owners who require it, while allowing for a less rigorous namespace for experimental and personal use.

By including the List-Id field, list servers can make it easier for mail clients to provide automated tools for users to perform list functions. The list identifier can serve as a key to make many automated processing tasks easier, and hence more widely available.

1. Introduction

Internet mailing lists have evolved into fairly sophisticated forums for group communication and collaboration; however, corresponding changes in the underlying infrastructure have lagged behind. Recent

Chandhok & Wenger Standards Track [Page 1]

RFC 2919 List-Id March 2001

proposals like [RFC2369] 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...