[petsc-users] Mailing list reply-to munging (was Any changes in ML usage between 3.1-p8 -> 3.3-p6?)

[Jed Brown]

Satish Balay <balay at mcs.anl.gov> writes:

> So it is a client side filtering. Curently there is no spam on the
> mailing lists - as it goes in for moderator approval. If we switch
> everyone will get spam - and users filters would have to take care of
> things. I guess gmail does it one way - but not everyone is on gmail.

Everyone with an email address gets sent spam so they must have some
filtering mechanism in place.  And no-subscription list traffic is not
necessary; we could keep the current moderation system.

> And then - if gmail spam fails because of "Reply-to: petsc-maint" -
> then thats a useless spam filter. RT doesn't have to set that
> field. Any spamer can do that trivially.

Yes, but they have to have done their homework to know that petsc-maint
has some significance to me.  If they did that much, they would always
send me email spoofed to look like it came from you, Barry, and my
girlfriend.  And every spam message to the Git list would be Reply-to:
Linus, etc.  But that doesn't happen, and even 

>> And header munging could be turned off without enabling anonymous
>> posting.
>
> yes thats possible. With that - we'll be trading off 'enabling users
> to subscribe-without-delivery' [who can easily use filters to prevent
> mailing list traffic flooding their mailbox] - at the cost of everyone
> remembering to 'reply-all' all the time.

John Doe sends email to petsc-users and the mailing list rewrites
Reply-To back to the list.  Now any user hits reply-all and their mailer
gives them a message that replies *only* to petsc-users, dropping the
original author.  This is a problem, and only a few mailers have a "when
>From and Reply-To do not agree, assume this is mailing list munging and
disregard the intent of the Reply-To field (RFC 2822) by also replying
to the address found in From" feature.

In other words, any mailer that interprets the Reply-To field as its
intended "instead of" semantics rather than "in addition to" will drop
the original author, meaning lost replies for people that are not
subscribed or have delivery disabled.

Perhaps a middle ground would be to have the list copy the From header
over to Reply-to (if it doesn't already exist) and then _add_ the list
address to Reply-to.  That still isn't quite right when cross-posting,
but it would allow us to advertise "subscribe with delivery off and ask
questions on the list" or even "mail the list without subscribing"
instead of "always write petsc-maint if you can't be bothered to filter
the high-volume list".