On 2007-06-07 08:31:22 -0700, JT Moree wrote: > Les Mikesell wrote: > >> some would argue that mail 'as designed' is broken already. Are you > >> talking about the type of forwarding where I can make it look like you > >> sent an email to someone else? > > > > No, I'm talking about the kind of forwarding that lets you have accounts > > in lots of places, which happens for lots of legitimate reasons, and > > having all your email land in one convenient place that itself might > > change from time to time. A college that permits alumni to keep their > <snip> > > I'm just thinking out loud ;). Why is it that the email has to forward > in such an anonymous manner such that SMTP servers should blindly just > do as they are told? > > Would it not be better for the forwarding mechanism (SMTP specs revamp?) > to wrap the old email in a new envelope and send it as an new transaction?
It does that, of course. Otherwise you wouldn't get the mail.
The new envelope contains the new recipient address but the old sender
address. There is no fixed address which can be substituted: The
original recipient address cannot be used because all mail to that
address gets forwarded to the new address (creates a nice loop in case
of an error and is completely useless if there is no error). The
postmaster of the forwarding system probably already gets enough mail.
SRS and similar schemes solve that by using a reversible mapping. For
each original sender address they create a new local sender address - if
they get a mail adressed to that local sender address they do the
reverse mapping and forward it to the original sender address. But you
need software to do this which needs to be installed on the server doing
the forwarding, which is most likely not using SPF: So why should the
admin of that server install that software?
> In that case, if the forwarding system is using spf or not it doesn't
> really matter.
That doesn't matter anyway. You have a problem if the original sender
and the new recipient are using SPF and the forwarding system in the
middle doesn't know about it.
> Whatever the contents, senders, or recipients of the original mail, it
> doesn't really matter. The messages would get forwarded and all the
> checks and balances would work better because the mail systems are not
> blindly passing mail around for other systems.
>
> Instead there is a break in the old transaction and a new transaction is
> started. Just like with real mail. When the PO forwards mail they
> re-address the envelope--essentially a new transaction--at least this is
> how forwarded mail comes to my box.
They change the recipient address, yes. But do they change the sender
address? I don't think so. So they do exactly the same thing as an SMTP
server using the .forward mechanism.
> It has a yellow sticker notifying
> me that I need to tell the original sender that the address has changed.
That's because the postal service doesn't want to deliver a letter twice
for the price of one delivery.
> That might be annoying to those who want the MUA to pretend that the
> mail came directly to them but is it more annoying than having to deal
> with the side effects of SPAM?
The MUA usually doesn't see the envelope.
hp
--
_ | Peter J. Holzer | I know I'd be respectful of a pirate
|_|_) | Sysadmin WSR | with an emu on his shoulder.
| | | [EMAIL PROTECTED] |
__/ | http://www.hjp.at/ | -- Sam in "Freefall"
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