Re: rfc2822bis -- adding clarifying Sender: text

At 10:23 19-01-2008, Pete Resnick wrote:
>Note: The transmitter information is always present. The absence of 
>the "Sender:" field is sometimes mistakenly taken to mean that the 
>agent responsible for transmission of the message has not been 
>specified. The absence of the "Sender:" field merely means that the 
>transmitter is identical to the author and is therefore not 
>redundantly placed into a separate field.

I prefer the above text to what is in Section 3.6.2 of the draft.

The current draft (draft-resnick-2822upd-04) has:

   "If the originator of the message can be indicated
    by a single mailbox and the author and transmitter are identical, the
    "Sender:" field SHOULD NOT be used.  Otherwise, both fields SHOULD
    appear."

I viewed RFC 2822 as saying that we "must" put in a Sender if it's 
different from the author.  If the author and the sender are the 
same, we "must not" put in the Sender header as it would be redundant.

On reading of the current draft, one may interpret that "SHOULD NOT" 
as saying that it is recommended not to put in a Sender field unless 
the circumstances dictate it.  To avoid "the circumstances" from 
being stretched, we can either use a "MUST NOT" or else use your 
note.  I favor your note as it's a clarification of the issue that 
was sought.  Here's a slightly modified version:

Note: The transmitter information is always present. The absence of 
the "Sender:" field is sometimes mistakenly taken to mean that the 
agent responsible for transmission of the message has not been 
specified.  This absence merely means that the transmitter is 
identical to the author and is therefore not redundantly placed into 
the "Sender:" field.

Regards,
-sm