+PH/11 There is a new log selector, "unknown_in_list", which provokes a log
+ entry when the result of a list match is failure because a DNS lookup
+ failed.
+
+PH/12 There is a new variable called $smtp_command which contains the full SMTP
+ command (compare $smtp_command_argument - see PH/07 above). This makes it
+ possible to distinguish between HELO and EHLO, and also between things
+ like "MAIL FROM:<>" and "MAIL FROM: <>".
+