On Fri, 23 Jan 2004 20:23:31 EST,
winserver(_dot_)support(_at_)winserver(_dot_)com said:
"client/server protocol compliant level" identification. SMTP should be =
given a "IETF VERSION" stamp, much like HTTP 1.0/2.0, etc. and it should =
be part of the protocol handshake (or possibly DNS MX lookup) that =
clients and servers can use to determine level of compliancy. While =
ELHO can be used to identify extensions, deployment is minimized by not =
having an enforcement statement in the functional specifications. =
The problem with a "version stamp" is that it imposes a strict partial ordering
on features. For example, if PIPELINE was included in SMTP 1.5, and SIZE was a
SMTP 1.8 feature, there's no clear way to implement SIZE without doing PIPELINE
as well. This can really be a headache if you have a resource-constrained
target (think "cell phone") where you *really* need SIZE so you can control
bandwidth usage, but you don't have the capacity to do PIPELINE (which is a lot
harder to get right than it looks at first glance).
You should go back in the old MIME working group discussions and read up on why
it wasn't believed we'd every have a 'Mime-Version: 2.0' header...
pgpM6EKMAuhMB.pgp
Description: PGP signature