netadmin(_at_)knotwork(_dot_)com asked,
| Hmmm yet I thought both smail and sendmail have priorities, in fact I know
| UUCP does also, such that some level of priority is lie priority post or
| personal email and and there is a priority known as junk or bulk.
Those are precedences, not priorities. Although the two words are nearly
synonymous in the English language, for email they have different meanings:
precedence is a guideline for treatment by the mail transports, and priority
is a guideline for treatment by the human recipients. So we have to be
careful of which term we're using.
| I thought that in the MTA somewhere is set what level among
| those to use for bulk?
While the Priority: header is read by human eyes and may contain anything
in any language (though "urgent" and "non-urgent" are common values), the
Precedence: header has several generally recognized possibilities, such as
"junk" or "bulk" for impersonal mailings (many MTAs, for example, will not
bother returning NDNs for undeliverable mail with bulk or junk precedence
or will not include the body of the undelivered letter when they report a
delivery failure, and "list" for by-subscription mailing lists (such as the
one on which we're discussing this).
Some MTAs recognize raised precedences, such as "special-delivery."
| I got the impression fro mthat that mail is
| expected to have a precedence when it arrives, in order that e.g. UUCP
| knows whether or not it is bulk or list or normal in order to decie which
| priority to assign it.
No, it is not necessary to specify a precedence. If the Precedence: header
is absent, the transports assume the normal importance of individual-to-
individual email.
| ###########################
| # Message precedences #
| ###########################
|
| Pfirst-class=0
| Pspecial-delivery=100
| Plist=-30
| Pbulk=-60
| Pjunk=-100
Yes, those are how sendmail will treat mail with recognized values in a
Precedence: header. No Precedence: header or an empty one is 0 (and so
is "Precedence: first-class").
| To what does the aboe chunk of sendmail.cf refer if not to some means of
| separating list, bulk, and junk mail from regular mail?
Not so much separating as distinguishing ... when cycles are at a premium,
special delivery mail gets more attention than ordinary mail but list, bulk,
and junk get less.