This note provides guidance on balancing the need to limit spam with preserving openness of IETF mailing lists.
The two extremes of mailing list operation run from a completely open list in which no submissions are rejected to moderated lists where a human reviewer must explicitely approve each submission. Neither approach is desirable in most cases. The more typical approach is to allow some types of messages to be distributed with no human check, while remaining messages are either rejected outright, or sent to a human reviewer for rejection or approval.
The definition of spam is subjective. For the purposes of this note, spam refers to messages that the vast majority of people subscribed to the mailing list would agree is spam (e.g., "make money fast"). When there is significant debate as to whether a message actually constitutes spam, it would appear that moderation rather than spam control is taking place and separate guidelines apply (e.g., see "IESG Guidance on the Moderation of IETF Working Group Mailing Lists").
The following guidelines apply to spam filtering on mailing lists:
1. It is assumed that messages submitted to a mailing list are categorized by a software filter into two categories: submissions from subscribers or other known email addresses and submissions from non-subscribers. Submissions from subscribers or other known email addresses are distributed immediately. Other submissions must then be made available to a human reviewer for further consideration.
2. WG Chairs (and/or some other designated WG member(s)) must review the list of held messages on a regular basis and have the opportunity to approve the distribution of non-spam submissions to the mailing list. Review of such messages should normally take place in a timely matter (i.e., within one business day).
3. The default action for the designated reviewer is to approve all messages that are not clearly spam. Doing otherwise changes the purpose from spam control to moderation and separate guidelines apply.
4. Any held message that is later approved for distribution on the mailing list should appear on the list as a normal posting (e.g., with the proper sender in the From address, etc.).
5. Mailing lists that check the sender's address as part of the determinate of what might be spam must also support a list of "known email addresses" whose submissions are automatically approved without human intervention. The list of "known email addresses" must include at least the following addresses:
plus any others for which an explicit request is made (e.g., a WG member who wishes to post from an address other than one that is subscribed to the list).
6. Appeals of decisions with regard to the rejection of specific messages should be handled through the normal RFC 2026 mechanisms. E.g., WG chairs, ADs, etc.
7. Comments on these guidelines should be directed to firstname.lastname@example.org