On 2008-05-22 15:34:10 -0400, John Leslie wrote:
> Peter J. Holzer <[EMAIL PROTECTED]> wrote:
> > I think most people these days use web interface to subscribe to
> > mailing-lists. People probably don't know their current BATV address, so
> > a user will enter '[EMAIL PROTECTED]' into the web form. He will get
> > the confirmation mail to this address, click on the confirmation url,
> > and get all the mails delivered to this address.
> 
>    Note that the opt-in confirmation presumably _will_ contain a BATV-
> coded MailFrom.

The user may not ever send a confirmation mail. For example, con
confirmation requests sent by mailman look like this:

| We have received a request from 192.0.2.7 for subscription of your
| email address, "[EMAIL PROTECTED]", to the [EMAIL PROTECTED]
| mailing list.  To confirm that you want to be added to this mailing
| list, simply reply to this message, keeping the Subject: header
| intact.  Or visit this web page:
| 
|     
http://example.net/mailman/confirm/community/59cf758b185b8c0dc5487b58321fc83fbe042ede
| 
[...]

I am sure many users will confirm by clicking on the URL and not by
replying to the message. So the mailing list software will not see the
BATV-coded MailFrom.


> > So it appears to work fine. Until he actually tries to send mail to the
> > list - the mail comes from [EMAIL PROTECTED], which
> > doesn't match the address he's subscribed with, so it will be rejected.
> 
>    To tell truth, that's broken.
> 
>    Requiring a MailFrom you've never seen isn't nearly as reasonable as
> requiring a 2822-From you have seen.

Actually, you haven't seen either a 2821-MailFrom or a 2822-From yet.
What you have seen is a 2821-RcptTo (You know that this works because
the user was able to click on the link in the message).


>    Nonetheless, if we observe such behavior in the wild,

ezmlm is the canonical example. Ned tells us that his mailinglists use
the envelope, too. I don't know if either uses a webbased subscription
mechanism like mailman, but I suspect they do.

> we should at the very least warn about it; and IMHO we should design
> in a workaround.

That's why I mentioned it.

        hp

-- 
   _  | Peter J. Holzer    | It took a genius to create [TeX],
|_|_) | Sysadmin WSR       | and it takes a genius to maintain it.
| |   | [EMAIL PROTECTED]         | That's not engineering, that's art.
__/   | http://www.hjp.at/ |    -- David Kastrup in comp.text.tex

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