On Fri, Dec 05, 2003 at 03:38:20AM -0500, John C Klensin wrote: > From a simple syntax standpoint, one option with an advertised > "prefer/ accept" parameter would do the job, and would be much > preferable architecturally to two options. Yes. > connection-time-limited What's a connection-time-limited environment? > And something batch-oriented also solves the "what to > do about those Received headers" problem As well as the the extra round-trip times problem associated with SMTP. A disadvantage of batch-oriented approaches is that mail rejection could happen later.