[Mailman-Developers] Re: way to minimize IO load with MTA supported VERP

[tneff@bigfoot.com]

--On Thursday, December 06, 2001 5:35 PM -0500 Peter W <peterw@usa.net> 
wrote:
> I like the basic idea a lot, but that doesn't look very backwards
> compatible, though. Why not something like
>  	MAIL FROM: mylist-owner@mydomain.com
>  	250 mylist-owner@mydomain.com... Sender ok
>  	RCPT TO: johnsmith@aol.com
>  	250 johnsmith@aol.com... Recipient ok
>       OVRD "MAIL FROM: johnsmith-aol.com-mylist-owner@mydomain.com"
>       250 per-recipient override of "MAIL" ok
>       DATA
>
> i.e., a new SMTP command, not a change in existing rules.

I guess I was a little afraid that MTA's would get lost matching up 
separately-issued RCPT TO: and OVRD commands that were supposed to function 
as logical pairs.  I think that the ESMTP syntax would not be gravely 
injured by adding another whitespace-separated atom after the TO: and 
address, but I might be wrong.

Another approach would be to add a VERP "mode" with a single command:

	VERP ON
	250 Variable envelope mode ok

so that subsequently saying

	MAIL FROM: mylist-owner@mydomain.com
and then
	RCPT TO: johnsmith@aol.com

would automatically ensure that the envelope sender for that message would 
be transformed according to a well-known rule, e.g.

	johnsmith-aol.com-mylist-owner@mydomain.com

I think this would do the least violence overall because if VERP isn't 
supported, no big deal, and the dialog syntax doesn't change in any other 
way.