A note dated  Tue, 7 Mar 1995 08:09:37 -0800  asked:
> To:             Multiple recipients of list LSTSRV-L
 
> Hi all,
>
> I've got a question.  I had a subscriber ask me about the Header=
> options.  I looked at the LISTSERV REFCARD (23 January 1995) which
> says:
>
> FULLbsmtp or FULLHdr          -> "Full" mail headers
> IETFhdr                       -> Interent-style headers
> SHORTbsmtp or SHORTHdr        -> Short (default) headers
> DUALhdr                       -> Dual headers, useful with PC
>                                  or Mac mail programs
>
> This isn't much information.  Can anybody elaborate on this?
 
This answer is based on what I've seen; if I miss by too much,
someone who knows the code ought to elaborate.
 
First, a user sets one of these options on his/her subscription to a
given list to control how the headers look on the mail that the list
sends to him/her.  Anyone, of course, can try the different settings
and see what they do.
 
Let's start with "Short" (default). Since this is the default, it may
well be what you see at the top of the note you are reading. The To:
is a stylized "To: Multiple recipients of list ....". The "Received"
lines that show the path the mail followed show the path from the
listserv to the recipient.
 
Next, consider "Full" headers. This is a proper superset of "Short".
Some additional lines are present, e.g. X-to:, which shows how the
original was addressed.
 
The "IETF" headers are not a sub- or super-set of those shown
previously. These headers appear to show as much as possible the
headers of the note that arrived at the listserv from the original
poster. I am on one list where people write in about their e-mail
problems, and I find "ietf" headers useful there, since they let me
learn the most about the poster's mail system.
 
Finally,  the "Dual" header option causes the listserv to make an
extra copy of the headers in the body of the note. This is invaluable
for people who are forced to use crippled mail systems that insist on
throwing away certain header lines. The most usual of these either do
not show the "Reply-to" or the "From" lines, where in listserv
contexts, both are needed (one shows the list, the other shows the
original poster). Getting "dual" headers gets past such a mailer by
placing the extra copy of the headers in the body where (with luck)
the mailer will not delete the information.
 
--
  Pete Hoyle - William & Mary Technology Services Computing Support
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