Re: Who sets Sender:?

[prj@po.cwru.edu (Paul Jarc)]

Stainless Steel Rat <ratinox@peorth.gweep.net> wrote:
> * prj@po.cwru.edu (Paul Jarc)  on Tue, 21 May 2002
> | Is the MUA supposed to be able to determine when Sender is needed?
>
> If the user fails to create a Sender header when it is required then the
> MUA needs to be able to do so.  In many (most?) cases the MUA must guess
> because it cannot read the minds of the originator or sender.

In what cases should the MUA guess that Sender is needed?

> | > and that an attempt has been made at getting the address correct if the
> | > user has not done so himself.
> | I can't find that criterion in RFC 2822.  Can you point it out?
>
> Definition of addr-spec plus requirements of RFC 2821 and the other
> protocols involved in mail handling.

Chapter and verse, please.

> | user@hostname is often not a working address - I'd say it's wrong more
> | often than right.
>
> ... if your site is configured properly, with a wildcard MX record for your
> entire (sub)domain pointing to your site's mail server, and aliases or
> mailer tables for mapping your users' login names to mailboxes, then
> user@hostname will always be a working address.

That requires a significant degree of cooperation among hosts at a
site; all usernames on all machines must be known to the mail server.
I don't think that's universally agreed-upon to be a "proper" policy,
and I don't think MUAs should assume this to be true any more than you
think networks should assume MUAs to be well-configured.

> Your solution, leaving the site broken and changing Gnus' default
> behaviour, may cause Gnus to construct illegal headers.

I never said the site should be left "broken"; we can have
well-configured networks *and* well-configured MUAs.  I've only said
that Gnus should not add Sender automatically.  In what circumstances
would that qualify as Gnus constructing illegal headers?

> Your solution addresses a symptom of a problem and may create
> another problem.  My solution addresses the problem and prevents
> other problems.  My solution, fixing the site and leaving Gnus
> alone, will never cause Gnus to create illegal headers.

You're trying to make every MUA work on your site.  I'm trying to make
Gnus work on every site - including the ones that aren't configured
the way you prefer.  This means catering in part to the cases where
user@hostname is not a working address, because Gnus is used in those
cases sometimes.

Since Sender is only for human consumption, and it is so difficult for
software to guess a correct value, and the sender might want to
conceal that information anyway, I think any attempt to add Sender
automatically is wasted effort.


paul