[Mailman-Developers] New RFC on using DKIM with MLMs

[Barry Warsaw]

On Oct 28, 2011, at 10:36 PM, Patrick Ben Koetter wrote:

>> >> From Mailman/Handlers/CookHeaders.py:
>> >> 
>> >>        msg['X-Mailman-Version'] = mm_cfg.VERSION
>> >> 
>> >> Seems to add the product version and not the User-Agent.
>> >
>> >Yes, but a User-Agent, header would have the product and the product version.
>> >A List-Agent header should do the same.
>> 
>> List-Agent is not a bad idea.
>
>It's not available in RFC 2369. We will have to propose 'List-Agent' as a new
>standard. Should we?

I think it makes sense to have a header identifying the MLM that the message
flowed through, and List-Agent seems like a good choice.

>> >>>> X-Mailman-Approved-At
>> >> 
>> >> From Mailman/ListAdmin.py:
>> >> 
>> >>            # Queue the file for delivery by qrunner.  Trying to deliver the
>> >>            # message directly here can lead to a huge delay in web
>> >>            # turnaround.  Log the moderation and add a header.
>> >>            msg['X-Mailman-Approved-At'] = email.Utils.formatdate(localtime=1
>> >
>> >So, I guess that the web moderation works by adding this header, so that
>> >the message can be delivered when the queue runner sees it. It looks like
>> >useful trace information, so it should stay.
>> >
>> >This also looks like a candidate for, say, a List-Approved-Date header.
>
>It's not available in RFC 2369. We will have to propose 'List-Approved-Date'
>as a new standard. Should we?

I also think it makes sense to have a date header marking the time when the
message was approved.  This implies of course that the message was held for
moderation.  Would there be a L-A-D header if the posting was automatically
accepted?  Maybe the header should be List-Posted-Date, although there some
subtly different semantics implied by that.  E.g. if the date the message was
approved isn't quite the date the message was posted (idk, some delay from
moderator acceptance to actually posting through the MLM).

Another header that might be useful here would be List-Approved-By which could
be the name or email address of the moderator who approved it.  Right now, MM3
doesn't fill that in, and it could of course be filled in by say
list-owner at example.com, but in MM3 it could be potentially filled in with the
preferred address for the moderator that approved it.

>> >> From Mailman/Handlers/Tagger.py:
>> >> 
>> >>    # For each regular expression in the topics list, see if any of the lines
>> >>    # of interest from the message match the regexp.  If so, the message gets
>> >>    # added to the specific topics bucket.
>> >
>> >So, is this used by Mailman to decide who to send the message to? Or is it
>> >supposed to help recipients to build filters. Either way, it might be useful
>> >for the latter purpose. Perhaps it's a candidate for List-Topics?
>> 
>> Are there any other MLMs that support topics in a way that would make that
>> header generally useful?
>
>Not that I am aware of. But maybe we could give it a more generic view. I
>could imagine calling them 'Tags', which would make them usable in any
>protocol that sends headers. 

Hmm, adopting a hash-tags format here would be kind of interesting for interop
with social networking sites.  It wouldn't have to be reflected in the name of
the header, but it could be SHOULD in the spec.  I ought to be pretty trivial
for MM3 generate hash-tags here.

What's interesting of course is that the Mailman module that fills this
information in is the tagger handler.

>> >> From the changelog:
>> >>          The archived copy of messages grows an X-List-Received-Date:
>> >>          header indicating the time the message was received by
>> >>          Mailman.
>> >> 
>> >> 
>> >>        # Always put an indication of when we received the message.
>> >> 
>> >>        Seems to decide where messages should be archived
>> >
>> >I think that's a candidate for a List-Archived-Date header. Because that's
>> >potentially helpful for people looking to find the message in an archive.
>> 
>> Possibly so, if it's a header added by the MLM.  E.g. an archiver might have
>> its own "archive date" value so it would either have to chose a different
>> header, or use multiple instances (with the loss of fidelity).
>
>When I read 'List-Archived-Date' I understand it specifies the date the
>message had been archived by some archival software and not the date is was
>sent to the archive by an MLM.

Yep, to me too.

>That makes a difference to me because copying the message to an archive might
>not be the only way to transport it there. The MLM might as well use an LMTP
>transport and queue it up for delivery. The queued message might get stuck in
>a delivery queue for hours. Being able to tell the difference between 'sent
>off to' and 'stored at' might be very useful to a postmaster when debugging
>archival problems.

Agreed.

>Choosing a more specific header field would probably also avoid getting into
>an archivers way when it creats an "archive date" value as Barry mentioned
>above.
>
>Not sure. Am I overly pedantic on this?

No, I think it's an important distinction.  Also note that in MM3 you can
actually have any number of archivers, so I think you want a field that
clearly describes the actions of the MLM.  I'm not sure what that would be
other than List-Archived-Date though. :/

Suggestions?

-Barry