On Mon, 11 Sep 2006, william(at)elan.net 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. Tony. -- f.a.n.finch <dot@dotat.at> http://dotat.at/ FISHER: WEST OR NORTHWEST 4 OR 5 BECOMING VARIABLE 3 OR 4. FAIR. MODERATE OR GOOD.