Re: Sender header?

[Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai Großjohann)]

On Thu, 24 May 2001, Stainless Steel Rat wrote:

> Before this gets too long, here is a hint: system-name.  Think about
> it for a moment.

system-name helps to find an IP address, but it does not
(particularly) help with sending mail.

> * Kai.Grossjohann@CS.Uni-Dortmund.DE (Kai Großjohann) on Thu, 24 May
>   2001
>| I dare say that people don't complain because people can frob their
>| From header via user-mail-address.  They cannot, however, frob
>| their Sender header via user-mail-address.
> 
> And they should not.  Frobbing it directly would be a violation of
> the requirements of RFCs 2822 and 1034.

Please quote chapter and verse.

> [...]
>|   - Generate a Sender header using user-login-name, followed by
>|     "@", followed by system-name.
> 
> Which is as canonical as a program can get.  Sender is supposed to
> be canonical.  By "canonical" I mean "an attempt has been made to
> ensure that the mailbox is valid".  For a correctly configured
> system, and that includes the mail hubs and what-not, not just the
> local machine, `login at FQDN' is canonical.
> 
> I apparantly misunderstood something, because using
> user-mail-address for generating Sender would break that.  Therefore
> it should not be done.

RFC 2822 has the following to say about the From and Sender headers.

/----
| The originator fields indicate the mailbox(es) of the source of the
| message.  The "From:" field specifies the author(s) of the message,
| that is, the mailbox(es) of the person(s) or system(s) responsible for
| the writing of the message.  The "Sender:" field specifies the mailbox
| of the agent responsible for the actual transmission of the message.
\----

Note that this talks about both headers containing mailbox
specifications.  It does not at all suggest that the mailbox
specifications in the Sender header should in any way differ from the
mailbox specifications in the From header.  It does not say that the
part after `@' should be a FQDN for the From header mailbox specs, nor
does it say this for the Sender header mailbox specs.

I don't see why you require the part after `@' to be a FQDN for the
Sender header, but not for the From header.

And: I don't see why the part before the `@' should be the login name
of the user.  I don't see this for the From header, and I don't see
this for the Sender header.

Can you point out where the RFC makes such a distinction between the
>From and the Sender headers?

> [...]
>| I don't know what does RFC 2822 say.  I only know about RFC 822.
>| The local RFC server doesn't seem to know about this RFC.  Can you
>| help out?
> 
> RFCs 2821 and 2822 obsoleted RFCs 821 and 822 about a month ago.
> They clarify a lot of things, not the least of which is Sender, both
> by standard and defacto use.

Sadly, the examples are not quite clear.  However, the Message-ID
headers mention local.machine.example as an `after-@' part.  Since the
`after-@' part in a Message-ID should be a FQDN, I conclude that
local.machine.example is intended to be a FQDN.

The examples for the Sender header use machine.example, which is NOT a
FQDN.

How can you require FQDN if even the examples in the RFC don't have
it?

> [...]
>| I'm with you so far.  I presume that you have set user-mail-address
>| to "ratinox@peorth.gweep.net".  Then my proposal does what you
>| want.
> 
> No, I don't.  I have my system configured correctly.  It knows
> itself as peorth.gweep.net, so Emacs knows it as peorth.gweep.net,
> so Gnus knows it as peorth.gweep.net, and nothing needs to be
> kludged.

Well, if you have configured system-name to be correct for your From
address, then you have the special case where the existing Gnus
algorithm and my proposed algorithm return the same result.

But this special case is not true for all people.

> You seem to believe that because only one person is involved in
> originating a message and submitting it that the one person has only
> one identity.

I don't think that.

kai
-- 
~/.signature: No such file or directory