Re: Microsoft Outlook (Express) bug..

[fred () CHEETAHMAIL COM (Frederik Lindberg)]

On Fri, 9 Jun 2000 21:57:16 -0700, Elias Levy wrote:

> Travis Ogdon <togdon () easystreet com>:
>
> This is also true for all messages with the following invalid headers:
>
> Return-Path: <>

This is a valid header for [double-]bounces, added at the time of final
delivery, in this case the POP3/IMAP server when the envelope sender is
NULL. See rfc1123:

      5.2.13  RFC-822 Message Specification: RFC-822 Section 4

         The syntax shown for the Return-path line omits the
possibility
         of a null return path, which is used to prevent looping of
         error notifications (see Section 5.3.3).  The complete syntax
         is:

             return = "Return-path"  ":" route-addr
                    / "Return-path"  ":" "<" ">"

         The set of optional header fields is hereby expanded to
include
         the Content-Type field defined in RFC-1049 [SMTP:7].  This
         field "allows mail reading systems to automatically identify
         the type of a structured message body and to process it for
         display accordingly".  [SMTP:7]  A User Agent MAY support this
         field.

-- Fred
Frederik Lindberg, CTO, CheetahMail