Expanded the mention of the $SIGNATURE environment variable to talk about the

three different ways to override "From:" header construction.  Also added
mh-tailor(5) to the "SEE ALSO" section.

diff --git a/man/post.man b/man/post.man
index 397901a..d5b9e4e 100644 (file)
--- a/man/post.man
+++ b/man/post.man
@@ -73,9 +73,37 @@ The `\-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).
 
-\fIPost\fR consults the environment variable \fB$SIGNATURE\fR to determine
-the sender's personal name in constructing the \*(lqFrom:\*(rq line of
-the message.
+Under normal circumstances, \fIpost\fR constructs the "From:" line of the
+message from the user's UNIX username, the full name from the GECOS field of the
+passwd file, and the fully-qualified name of the local machine (e.g. `From: "Dan
+Harkless" <dan@machine.company.com>').  However, there are three ways to
+override these values.  Note that they apply equally to "Resent-From:" lines in
+messages sent with \fIdist\fR.
+
+The first way is GECOS-based username masquerading.  If "mmailid" in the
+mts.conf file has been set to non-zero, this processing is activated.  If a
+user's GECOS field in the passwd file is of the form "Full Name <fakename>" then
+"fakename" will be used in place of the real username.  For instance, a GECOS
+field of "Dan Harkless <Dan.Harkless>" would result in `From: "Dan Harkless"
+<Dan.Harkless@machine.company.com>'.  Naturally if you were doing something like
+this you'd want to set up an MTA alias (e.g. in /etc/aliases) from, for
+instance, "Dan.Harkless" to "dan".
+
+The second way to override default construction of "From:" is to set the
+\fB$SIGNATURE\fR environment variable.  This variable overrides the full name
+from the GECOS field, even if GECOS-based masquerading is being done.
+
+The third way, which will override either of the previous two, is to specify a
+"From:" line manually in the message draft.  It will be used as provided (after
+alias substitution), but to discourage email forgery, the user's real address
+will be used in the SMTP envelope "From:" and in the "Sender:" line.  However,
+if the system administrator has allowed address masquerading by setting
+"mmailid" to non-zero in mts.conf, the SMTP envelope "From:" will use the
+address given in the draft "From:", and there will be no "Sender:" header.  This
+is useful in pretending to send mail "directly" from a remote POP3 account, or
+when remote email robots give improper precedence to the envelope "From:".  Note
+that your MTA may still reveal your real identity (e.g. sendmail's
+"X-Authentication-Warning:" header).
 
 .Fi
 ^%etcdir%/mts.conf~^nmh mts configuration file
@@ -87,7 +115,7 @@ the message.
 .Sa
 \fIStandard for the Format of ARPA Internet Text Messages\fR (RFC\-822),
 .br
-mhmail(1), send(1), mh\-mail(5), mh\-alias(5)
+mhmail(1), send(1), mh\-mail(5), mh\-alias(5), mh\-tailor(5)
 .De
 `\-alias %etcdir%/MailAliases'
 .Ds