.\"
.\" %nmhwarning%
.\" $Id: post.man,v 1.11 2007/04/10 22:12:26 jjr Exp $
.\"
.TH POST %manext8% "%nmhdate%" MH.6.8 [%nmhversion%]
.SH NAME
post \- deliver a message
.SH SYNOPSIS
.HP 5
.na
.B %libdir%/post 
.RB [ \-alias
.IR aliasfile ]
.RB [ \-filter
.IR filterfile ]
.RB [ \-nofilter ]
.RB [ \-format " | " \-noformat ]
.RB [ \-mime " | " \-nomime ]
.RB [ \-msgid " | " \-nomsgid ]
.RB [ \-verbose " | " \-noverbose ]
.RB [ \-watch " | " \-nowatch ]
.RB [ \-width
.IR columns ]
.RB [ \-sasl ]
.RB [ \-saslmech
.IR mechanism ]
.RB [ \-user
.IR username ]
.I file
.RB [ \-version ]
.RB [ \-help ]
.ad
.SH DESCRIPTION
.B Post
is the default program called by
.B send
to deliver
the message in
.I file
to local and remote users.  In fact, most of
the features attributed to
.B send
in its manual page are performed by
.BR post ,
with
.B send
acting as a relatively simple preprocessor.
Thus, it is
.B post
which parses the various header fields, appends
\*(lqFrom:\*(rq and \*(lqDate:\*(rq lines, and interacts with the mail transport system.
.B Post
will not normally be called directly by the user.
.PP
.B Post
searches the \*(lqTo:\*(rq, \*(lqcc:\*(rq, \*(lqBcc:\*(rq,
\*(lqFcc:\*(rq, and \*(lqResent\-xxx:\*(rq header lines of the specified
message for destination addresses, checks these addresses for validity,
and formats them so as to conform to ARPAnet Internet Message Format
protocol, unless the
.B \-noformat
flag is set.  This will normally cause
\*(lq@\fIlocal\-site\fR\*(rq to be appended to each local destination
address, as well as any local return addresses.  The
.B \-width
.I columns
switch can be used to indicate the preferred length of the header
components that contain addresses.
.PP
If a \*(lqBcc:\*(rq field is encountered, its addresses will be used for
delivery, and the \*(lqBcc:\*(rq field will be removed from the message
sent to sighted recipients.  The blind recipients will receive an entirely
new message with a minimal set of headers.  Included in the body of the
message will be a copy of the message sent to the sighted recipients.
If
.B \-filter
.I filterfile
is specified, then this copy is filtered
(re\-formatted) by
.B mhl
prior to being sent to the blind recipients.
Alternately, if the
.B \-mime
switch is given, then
.B post
will use
the MIME rules for encapsulation.
.PP
The
.B \-alias
.I aliasfile
switch can be used to specify a file that post
should take aliases from.  More than one file can be specified, each
being preceded with
.BR \-alias .
In any event, the primary alias file is
read first.
.PP
The
.B \-msgid
switch indicates that a \*(lqMessage\-ID:\*(rq or
\*(lqResent\-Message\-ID:\*(rq field should be added to the header.
.PP
The
.B \-verbose
switch indicates that the user should be informed of
each step of the posting/filing process.
.PP
The
.B \-watch
switch indicates that the user would like to watch the
transport system's handling of the message (e.g., local and \*(lqfast\*(rq
delivery).
.PP
Under normal circumstances,
.B post
constructs the \*(lqFrom:\*(rq line of the
message from the user's login name, the full name from the GECOS field of the
passwd file, and the fully\-qualified name of the local machine (or the
value of
\*(lqlocalname\*(rq in
.IR mts.conf ,
if set).  An example is \*(lqFrom: Dan Harkless
<dan@machine.company.com>\*(rq.  There are four ways to override these values,
however.  Note that they apply equally to \*(lqResent\-From:\*(rq lines in messages sent
with
.BR dist .
.PP
The first way is GECOS\-based username masquerading.  If the \*(lqmasquerade:\*(rq line
in
.I mts.conf
contains \*(lqmmailid\*(rq, this processing is activated.  If a user's GECOS
field in the passwd file is of the form \*(lqFull Name <fakename>\*(rq then \*(lqfakename\*(rq
will be used in place of the real username.  For instance, a GECOS field of \*(lqDan
Harkless <Dan.Harkless>\*(rq would result in \*(lqFrom: Dan Harkless
<Dan.Harkless@machine.company.com>\*(rq.  Naturally if you were doing something like
this you'd want to set up an MTA alias (e.g. in /etc/aliases) from, for
instance, \*(lqDan.Harkless\*(rq to \*(lqdan\*(rq.
.PP
The second way to override default construction of \*(lqFrom:\*(rq is to set the
.B $SIGNATURE
environment variable.  This variable overrides the full name
from the GECOS field, even if GECOS\-based masquerading is being done.  This
processing is always active, and does not need to be enabled from
.IR mts.conf .
.PP
The third way is controlled by the \*(lquser_extension\*(rq value of \*(lqmasquerade:\*(rq line
of
.IR mts.conf .
When that's turned on, setting the
.B $USERNAME_EXTENSION
environment variable will result in its value being appended the user's login
name.  For instance, if I set
.B $USERNAME_EXTENSION
to \*(lq+www\*(rq, my \*(lqFrom:\*(rq
line will contain \*(lqDan Harkless <dan+www@machine.company.com>\*(rq (or
\*(lqDan.Harkless+www\*(rq if I'm using mmailid masquerading as well).  Recent versions
of
.B sendmail
automatically deliver all mail sent to
.IR user + string
to
.IR user .
.B qmail
has a similar feature which uses '\-' as the delimiter by
default, but can use other characters as well.
.PP
The fourth method of address masquerading is to specify a \*(lqFrom:\*(rq line manually
in the message draft.  It will be used as provided (after alias substitution),
but normally, to discourage email forgery, the user's
.B real
address will be
used in the SMTP envelope \*(lqFrom:\*(rq and in a \*(lqSender:\*(rq header.  However, if the
\*(lqmasquerade:\*(rq line of
.I mts.conf
contains \*(lqdraft_from\*(rq, the SMTP envelope \*(lqFrom:\*(rq
will use the address given in the draft \*(lqFrom:\*(rq, and there will be no \*(lqSender:\*(rq
header.  This is useful in pretending to send mail \*(lqdirectly\*(rq from a remote POP3
account, or when remote email robots give improper precedence to the envelope
\*(lqFrom:\*(rq.  Note that your MTA may still reveal your real identity (e.g.
.BR sendmail 's
\*(lqX\-Authentication\-Warning:\*(rq header). 
.PP
If
.B nmh
has been compiled with SASL support, the
.B \-sasl
switch will enable
the use of SASL authentication with the SMTP MTA.  Depending on the
SASL mechanism used, this may require an additional password prompt from the
user (but the
.RI \*(lq \&.netrc \*(rq
file can be used to store this password).
.B \-saslmech
switch can be used to select a particular SASL mechanism,
and the the
.B \-user
switch can be used to select a authorization userid
to provide to SASL other than the default.
.PP
Currently SASL security layers are not supported for SMTP.
.BR nmh 's
SMTP SASL code
will always negotiate an unencrypted connection.  This means that while the SMTP
authentication can be encrypted, the subsequent data stream can not.  This is in
contrast to
.BR nmh 's
POP3 SASL support, where encryption is supported for both the
authentication and the data stream.

.SH FILES
.fc ^ ~
.nf
.ta \w'%etcdir%/ExtraBigFileName  'u
^%etcdir%/mts.conf~^nmh mts configuration file
^%etcdir%/MailAliases~^global nmh alias file
^%bindir%/refile~^Program to process Fcc:s
^%libdir%/mhl~^Program to process Bcc:s
.fi

.SH "PROFILE COMPONENTS"
.B post
does
.B NOT
consult the user's
.I \&.mh\(ruprofile

.SH "SEE ALSO"
mhmail(1), send(1), mh\-mail(5), mh\-alias(5), mh\-tailor(5),
.I "Standard for the Format of ARPA Internet Text Messages"
(RFC\-822)

.SH DEFAULTS
.nf
.RB ` \-alias "' defaults to %etcdir%/MailAliases"
.RB ` \-format '
.RB ` \-nomime '
.RB ` \-nomsgid '
.RB ` \-noverbose '
.RB ` \-nowatch '
.RB ` "\-width\ 72" '
.RB ` \-nofilter '
.fi

.SH CONTEXT
None

.SH BUGS
\*(lqReply\-To:\*(rq fields are allowed to have groups in them according
to the 822 specification, but
.B post
won't let you use them.