A note from the list manager...to keep in mind.

Frequently-asked Mailing List questions:

  1. Is the list open?
  2. Is the list moderated?
  3. What posting policies apply to the list?
  4. Why is a particular list not subscriber-only?
  5. If a list is subscriber-only, and I'm on a sub-list, how can I post?
  6. How can I post to a subscriber-only list from multiple email accounts without receiving multiple list posts?
  7. What SPAM filters to you use?
  8. I got a "suspicious header" message - what does that mean?
  9. Mail was 'held for because poster is not a list member" on a subscriber-only list; should I repost it?
  10. Why are posts using X-no-archive held or bounced?
  11. My mail has been held for review; how long does review take?
  12. Can I discuss these policies on the mailing list?
  13. Do you particiapte in these discussions?
  14. Will you change these policies?

A note from the list moderator.

Lists on postel.org are configured based on thoughtful consideration of both the available resources and benefit to list subscribers. In particular:


  • All postel.org lists are subscriber-only post. This has been needed to limit the impact of spam.
  • Subscriber-only lists require that posters subscribe to the list before a post is accepted.
  • Non-subscriber posts are "held for approval." Because spam is equally "held for approval", nearly all "held" messages are discarded. Click here for more info.


  • All lists are configured upon thoughtful consideration of both the available resources and list subscribers. While list configuration can be discussed on the lists, it is ultimately a matter of social engineering rather than democratic rule.
  • All lists use content-based automatic SPAM filters and manual policy filters. SPAM filtering is performed primarily to reduce network bandwidth; it is not a substitute for receiver-side filters. Subscribers are encouraged to use their own filters in addition to ours.

These policies are posted here to avoid redundent discussion on the mailing list. As such, we will forward a pointer to the FAQ when a relevant discussion begins.

Is the list open?

Anyone can join our lists, but subscription is required prior to posting. Note that you must be subscribed from the e-mail address from which you are posting; see information here if you post from multiple addreses.

Is the list moderated?

These lists are only partly moderated. Regular posts are not reviewed, and are posted automatically. Posts which trigger our filters may be held for review.

Our filters are designed to enforce list policies. E.g., on end2end-interest, CFPs must be approved in advance, and job posts are prohibited. Such posts are held for review. All other posts are forwarded to the list.

What posting policies apply to the list?

List posts are expected to be on-topic and to follow general behavior for appropriate use of public forum.

Appropriate use is defined as professional conduct. This includes avoiding posts that include attacks of a personal nature (ad hominems), publicly offensive material, or deliberate misrepresentations. Lists are not to be used to advocate candidacy for any office, whether a declared candidate or not, by the candidate or any other advocate.

Postings may be held or automatically discarded because of one of a number of reasons:

  • sender must be a list subscriber (from the address posted from)
  • message too big
  • message includes attachments
  • message uses the list as an implicit destination (bcc, cc)
  • message includes too many recipients
  • violation of list posting policies

Lists are not to be used for job announcements, and only a very few Call-for-Paper announcements are appropriate. Posts such posts are expected to:

  • have a primary focus on the topic of the list
  • focus on research discussion
  • be open to all participants (space permitting)

If you wish to send a CFP or any other sort of administrative announcement to these lists, please check first with the list owner and manager, Joe Touch ([email protected]). Otherwise, don't.

Additionally, for CFPs approved for posting, at most ONE call for contributions and ONE call for participation are permitted per pre-approved meeting - this includes adjunct workshops, tutorials, poster sessions, etc. (two separate calls for paper are permitted where the first call for papers includes a call for proposals for workshops, to allow a second call for papers for the workshops themselves).

Why are lists subscriber-only?

This is required to avoid the impact of spam..

If a list is subscriber-only, and I'm on a sub-list, how can I post?

Join the list, and request the "no mail" option.

How can I post to a subscriber-only list from multiple email accounts without receiving multiple list posts?

Join the list for each email you use as a source address, and request the "no mail" option for each.

What SPAM filters do you use?

We use two kinds of SPAM filters:

  1. Content-based automatic SPAM filters
  2. Static manual filters to enforce list policy

We do not use subscriber-list (white-list) filters, since they would increase the hurdle to casual users, users who post from multiple accounts, or users who subscribe via exploder lists.

I got a "suspicious header" message - what does that mean?

"Suspicious header" is what our mail system forwards to you when your post is held due to our filters, regardless of the specific issue. Our filters insert a "hold for approval" header flag, and the mail system is configured to consider that flag 'suspicious'.

It simply means your post has been held for approval (if this is subscriber-only list, you MUST repost). Mail is held when it potentially conflicts with list policy. E.g., job postings, book advertisements, and commercial conferences are prohibited from most lists on this server. There are also list-specific policies, e.g., end2end-interest permits at most one call for papers and one call for participation per pre-approved conference per year. Please see the list pages for list-specific policies.

Please keep in mind that the hold filers are designed to reduce false negatives (real violations that go through), and so generate false positives. Receiving this "suspicious header" message is not an indication that the post conflicts with list policy, and when such posts are reviewed a do not, they are forwarded to the list.

Mail was 'held because poster is not a list member" on a subscriber-only list; should I repost it?

If you have a post which is "held" because you are not a subscriber, you must REPOST after subscribing. If the post is still held for some other reason (tripping a spam filter, or filters on the list policy, e.g., CFPs), please FORWARD A COPY TO THE LIST ADMINISTRATOR ({listname}[email protected], e.g., [email protected]). Such forwards should NOT include attachments or be MIME-encoded. Short, ASCII posts will be forwarded when time permits.

Mail was held/rejected with x-no-archive?

If you have a post which is "held" or rejected because you used "x-no-archive: yes", it is because use of these lists is contingent on our software archiving the posts. We do not permit posts which are not archived.

My mail has been held for review; how long does review take?

On open lists, posts held for review are forwarded immediately upon review. Review can occur in a few minutes, a few hours, or as many as 1-2 days. Each list currently has only one reviewer, and so reviews are subject to business hours, holidays, and network access variations.

On subscriber-only lists, posts held for review are discarded, due to the large number of spam messages which are held in the same queue. In this case, please repost (click here for more info.).

Can I discuss these policies on the mailing list?

Certainly, as long as the discussion is productive and congenial (as with any discussion on the list). Please include one of the following headers, so others can filter such discussions out if desired:


  • - for general list operation and configuration:
  • - for discussions about spam on the list:


Specific issues can be appended, e.g., "LIST CONFIG - open or closed"

Such discussion is subject to the individual list; e.g., discussions of spam on end2end-interest are no longer welcome.

Do you (the list admin) particiapte in these discussions?

Sometimes, notably when the issues on this FAQ warrant clarification.

If you have a specific question that you want answered by the list maintainer, please post to the list maintainer directly (<listname>-owner).

Will you change these policies?

Of course. The configuration of these lists, and the policies by which they are operated, are always under review.

Keep in mind, however:

  • Many lists have several thousand subscribers. No single configuration will satisfy all subscribers.
  • List configuration is determined for the best interest of the list, based on the list's purpose, and in discussion with the list owner/originator (which may not be the list maintainer).
  • List configuration is determined by thoughtful consideration, closer to a republic than a democracy, FWIW.