H_ACHECK Header Flag (V5 and Later)
The H_ACHECK flag marks a header that should normally
be discarded unless a delivery agent’s F=
flag calls for its
inclusion. It is usually set for the Bcc
: header, which is
discarded for the privacy of a blind carbon copy
list, and the Full-Name:
header, which is intended as
a way for a user to add a full name (see the
$x
macro, $x on page 851) when there is no
full name defined in the
passwd(5) file. Note that
H_ACHECK, when combined with bogus ?
flags
?
of a header
configuration file declaration, can cause
appropriate headers to always be deleted or
replaced. Also note that under V8
sendmail, the H_ACHECK flag
alone always causes a header to be
replaced.
Replace headers with H_ACHECK
Some MUAs tend to insert their own Message-ID:
header
(Message-ID: on page 1159).
This can cause difficulty when tracing email
problems because those MUA headers lack the
sendmail queue identifier. At
sites that have a central mail hub machine, where
client machines forward all mail to the hub, you
can solve this problem by redefining Message-ID
: in
conf.c on the clients, to
delete the bogus Message-ID:
, so that a good one can be
generated on the hub:
"message-id", 0,
"message-id", H_ACHECK, ← change to this
Here, we changed the 0
flag for the Message-ID
: header into an H_ACHECK
flag. We do this only on the client machine
versions of sendmail but
not on the hub. The Message-ID
: header will then be stripped from every outgoing message on every client machine and a new ...
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