add hint for debugging

pb4sd/pb4sd

@@ -213,7 +213,10 @@ while (1) {
         $t->{$ipaddr} = $expire;
 
         #   skip if ip was already enabled
-        next if $already_enabled;
+        if ($already_enabled) {
+            $log->print("[".localtime($now)."] UPD client=".$ipaddr." logout=".localtime($expire)."\n");
+            next;
+        }
 
         #   lock database
         flock(DB_FH, LOCK_EX);
@@ -267,5 +270,9 @@ logfile for successful client authentications and writes the
 corresponding IP addresses into a Berkeley-DB hash file. This hash file
 then can be used by the MTA to allow relaying access.
 
+For debugging purposes you can dump the generated hash file with
+Berkeley-DB's C<db_dump -p> and query it selectively via Postfix's
+C<postmap -q>.
+
 =cut