Re: [EAI] double angle brackets

[John C Klensin <klensin at jck.com>]

--On Tuesday, September 08, 2009 22:04 +0000 Shawn Steele
<Shawn.Steele at microsoft.com> wrote:

> How do you tell multiple from meaning EAI apart from non-EAI
> multiple from?

I don't think you need to.

If I correctly understand the point that Ernie was trying to
make, there are the following cases:

	* non-EAI, support for multiple "From:": will accept
	both and probably discard the i18n email address.
	
	* non-EAI, no support for multiple "From:": Will reject
	either both addresses or the second one.  If one is
	accepted, probably the first one (which should probably
	be the ASCII address) will probably be used.  If both
	are rejected, then nothing much is lost compared to the
	failed downgrade case -- especially if you remember that
	an EAI envelope is unlikely to reach a non-EAI system.
	
	* EAI compliant system: will support multiple "From:"
	because the spec will require it.  

Then the EAI-compliant system will either respond to both
addresses on "reply" or to just the EAI one, but that is
consistent with how much we've historically underspecified what
to do with multiple "From:" situations.

The analysis for Reply-to won't be significantly different, IMO.

   john