Re: draft-crocker-email-deliveredto

It appears that George Michaelson  <[email protected]> said:
>The utility of having envelope available in canonical form for eg
>procmailrc or delivermail processing is high. I know I'd want this and
>have argued with operators of my MTA about it in the past.

This version of the draft is better but it it still says nothing about
the existing use of Delivered-To.

Postfix, Courier and qmail have added Delivered-To for a very long
time, more than 20 years for qmail. They use it for loop detection. If
a message already has the same Delivered-To it's about to add, they
bounce the message. Exim adds a similar header but calls it
Emvelope-To:. 

It turns out not to be useful for procmail. MTAs invariably have other
ways to tell procmail what the current delivery address is, via a command
line argument or environment variable, and it's up to the local
configuration whether to add the Delivered-To before the message is
passed to procmail.

R's,
John