-To support this, there are two variables. <ref id="dsn_notify"
-name="$dsn_notify"> is used to request receipts for
-different results (such as failed message, message delivered, etc.).
-<ref id="dsn_return" name="$dsn_return"> requests how much
-of your message should be returned with the receipt (headers or full
-message). Refer to the man page on sendmail for more details on DSN.
+Users can make use of it in one of the following two ways:
+
+<itemize>
+ <item>Berkeley sendmail 8.8.x currently has some command line options
+ in which the mail client can make requests as to what type of status
+ messages should be returned.
+ <item>The SMTP support via libESMTP supports it, too.
+</itemize>
+
+To support this, there are two variables:
+
+<itemize>
+
+ <item><ref id="dsn_notify" name="$dsn_notify"> is used
+ to request receipts for different results (such as failed message,
+ message delivered, etc.).
+
+ <item><ref id="dsn_return" name="$dsn_return"> requests
+ how much of your message should be returned with the receipt
+ (headers or full message).
+
+</itemize>
+
+Please see the reference chapter for possible values.