My understanding is that the Precedence header is an arbitrary
convention and IS NOT required as defined by any RFC. Apparently,
Eric Allman (author of Sendmail and the original *nix vacation
program) created it as a means of identifying which messages his
vacation autoresponder should not respond to.
As with many things good and wonderful, SPAM broadcasters are
ruining the usefulness of such a header comment. (What spammer in
their right mind willingly identifies their spam as spam?) Many
anti-spam filters automatically flag anything with the following
headers:
Precedence: list
Precedence: bulk
Precedence: junk
So, if it weren't for spam, these would be useful. But some list
sending applications, like Listserv, haven't implemented this as
a feature because they are non-standard. Lyris doesn't require
the precedence header, but you can add it if you want.
This is the only relevant comment I could find from the RFCs:
Precedence: Non-standard, controversial.
Sometimes used as a priority value which can influence
transmission speed and delivery. Common values are "bulk" and
"first-class". Other uses is to control automatic replies and
to control return-of-content facilities, and to stop mailing
list loops.
RFC 2076
Common Internet Message Header Fields
http://www.faqs.org/rfcs/rfc2076.html
Regards,
Rich.
--
Richard Tatum
Website manager for Christianity Today International
email: rich@christianitytoday.com
web: christianitytoday.com
aol im: richtatum
«The flood of careless, unconsidered, cheap words, is the
greatest enemy of the profound word» —Stephen L. Talbott
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