-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).
+The third way is controlled by the "plussed_user" value of "masquerade:" line of
+mts.conf. When that's turned on, setting the $USERPLUS environment variable
+will result in its value being tacked onto the user's login name, following
+a '+' sign. For instance, if I set $USERPLUS to "www", my "From:" line will
+contain "Dan Harkless <dan+www@machine.company.com>" (or "Dan.Harkless+www" if
+I'm using mmailid masquerading as well). Recent versions of sendmail
+automatically deliver all mail sent to \fIuser\fR+\fIstring\fR to \fIuser\fR.
+
+The fourth method of address masquerading is to specify a "From:" line manually
+in the message draft. It will be used as provided (after alias substitution),
+but normally, to discourage email forgery, the user's \fIreal\fR address will be
+used in the SMTP envelope "From:" and in a "Sender:" header. However, if the
+"masquerade:" line of mts.conf contains "draft_from", 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).