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Re: comast email issues, who else has them?

  • From: Tony Finch
  • Date: Mon Sep 11 14:53:57 2006

On Mon, 11 Sep 2006, william(at) wrote:
> On Mon, 11 Sep 2006, Tony Finch wrote:
> >
> > Far better to use a Received: header stating HTTP in the "with"
> > protocol field. (And the IANA registry should be updated to include
> > that as one of the standard values.)
> That suggestion is likely to be contrary to SMTP design. Received trace
> fields are for use of recording of where data that was RFC2822 formatted
> came from and how. Use of these fields also assumes that start of email
> transmission took place somewhere else.

I'm not entirely convinced by that argument. You could squint a bit
and view webmail as a sort of gatewaying, in which case it makes sense to
map webby concepts onto 821 and 822 as accurately as possible. The other
reason for using Received: for this kind of job is it scales better to
other submission methods: what about an XMPP-to-email gateway, for
example? It would be madness to define ad-hoc X- headers for each
submission protocol.

> The "with" clause in Received is used to indicate the "transport"
> protocol but assumes that data itself is already properly formatted
> (compare to that the same type of L7 protocol can use either TCP or UDP;
> this is not perfect fit but gives you some idea).

What about "with MMS" where the message format is not (quite) 822?

> If you really want to indicate the source of transmission for non-SMTP
> origination point, the best is to create new trace field for this purpose.
> With Received the closest clause would be "via" but I think via is largely for
> use with complete message being gatewayed through non-SMTP protocol and this
> is probably not the correct use of it either.

The only non-TCP via defined at the moment is UUCP, which I guess implies
batch SMTP - i.e. "via" is the level under the message transport protocol.

f.a.n.finch  <[email protected]>