diff -ur mailman-2.1.12.orig/Mailman/Defaults.py.in mailman-2.1.12/Mailman/Defaults.py.in
--- mailman-2.1.12.orig/Mailman/Defaults.py.in	2009-08-05 14:08:56.000000000 +0200
+++ mailman-2.1.12/Mailman/Defaults.py.in	2009-08-07 12:31:28.000000000 +0200
@@ -1163,6 +1163,8 @@
 DEFAULT_BOUNCE_NOTIFY_OWNER_ON_DISABLE = Yes
 DEFAULT_BOUNCE_NOTIFY_OWNER_ON_REMOVAL = Yes
 
+# Default discard E-mails without valid commands in command mode
+DEFAULT_DISCARD_EMAIL_WITHOUT_COMMAND = Yes 
 
 
 #####
diff -ur mailman-2.1.12.orig/Mailman/MailList.py mailman-2.1.12/Mailman/MailList.py
--- mailman-2.1.12.orig/Mailman/MailList.py	2009-02-23 22:23:35.000000000 +0100
+++ mailman-2.1.12/Mailman/MailList.py	2009-08-05 14:10:06.000000000 +0200
@@ -420,6 +420,9 @@
         self.scrub_nondigest = mm_cfg.DEFAULT_SCRUB_NONDIGEST
         # automatic discarding
         self.max_days_to_hold = mm_cfg.DEFAULT_MAX_DAYS_TO_HOLD
+        # discards email with no command
+        self.discard_email_without_command = \
+	    mm_cfg.DEFAULT_DISCARD_EMAIL_WITHOUT_COMMAND
 
 
     #
diff -ur mailman-2.1.12.orig/Mailman/Queue/CommandRunner.py mailman-2.1.12/Mailman/Queue/CommandRunner.py
--- mailman-2.1.12.orig/Mailman/Queue/CommandRunner.py	2009-02-23 22:23:35.000000000 +0100
+++ mailman-2.1.12/Mailman/Queue/CommandRunner.py	2009-08-05 20:31:06.000000000 +0200
@@ -53,6 +53,10 @@
     True = 1
     False = 0
 
+# Enumerate return codes
+CmdSuccess = 0
+CmdFailure = 1
+CmdMissing = 2
 
 
 class Results:
@@ -104,15 +108,19 @@
     def process(self):
         # Now, process each line until we find an error.  The first
         # non-command line found stops processing.
-        stop = False
+        found = CmdMissing
+        ret = CmdMissing
         for line in self.commands:
             if line and line.strip():
                 args = line.split()
                 cmd = args.pop(0).lower()
-                stop = self.do_command(cmd, args)
-            self.lineno += 1
-            if stop:
+                ret = self.do_command(cmd, args)
+            if ret != CmdMissing:
+            	found = ret
+            if self.lineno > 0 and ret != CmdSuccess:
                 break
+            self.lineno += 1
+	return found
 
     def do_command(self, cmd, args=None):
         if args is None:
@@ -135,7 +143,8 @@
                 self.subjcmdretried += 1
                 cmd = args.pop(0)
                 return self.do_command(cmd, args)
-            return self.lineno <> 0
+	    # Unknown command:
+	    return CmdMissing
         return handler.process(self, args)
 
     def send_response(self):
@@ -234,18 +243,24 @@
         # This message will have been delivered to one of mylist-request,
         # mylist-join, or mylist-leave, and the message metadata will contain
         # a key to which one was used.
+        ret = CmdMissing
         try:
             if msgdata.get('torequest'):
-                res.process()
+                ret = res.process()
             elif msgdata.get('tojoin'):
-                res.do_command('join')
+                ret = res.do_command('join')
             elif msgdata.get('toleave'):
-                res.do_command('leave')
+                ret = res.do_command('leave')
             elif msgdata.get('toconfirm'):
                 mo = re.match(mm_cfg.VERP_CONFIRM_REGEXP, msg.get('to', ''))
                 if mo:
-                    res.do_command('confirm', (mo.group('cookie'),))
-            res.send_response()
-            mlist.Save()
+                    ret = res.do_command('confirm', (mo.group('cookie'),))
+            if ret == CmdMissing and mlist.discard_email_without_command:
+	        # Discard messages with no valid command
+	        syslog('vette', 'No valid command, message discarded, msgid: %s',
+                       msg.get('message-id', 'n/a'))
+	    else:
+                res.send_response()
+                mlist.Save()
         finally:
             mlist.Unlock()
diff -ur mailman-2.1.12.orig/Mailman/Version.py mailman-2.1.12/Mailman/Version.py
--- mailman-2.1.12.orig/Mailman/Version.py	2009-02-23 22:23:35.000000000 +0100
+++ mailman-2.1.12/Mailman/Version.py	2009-08-07 12:55:02.000000000 +0200
@@ -37,7 +37,7 @@
                (REL_LEVEL << 4)  | (REL_SERIAL << 0))
 
 # config.pck schema version number
-DATA_FILE_VERSION = 97
+DATA_FILE_VERSION = 98
 
 # qfile/*.db schema version number
 QFILE_SCHEMA_VERSION = 3
diff -ur mailman-2.1.12.orig/Mailman/versions.py mailman-2.1.12/Mailman/versions.py
--- mailman-2.1.12.orig/Mailman/versions.py	2009-02-23 22:23:35.000000000 +0100
+++ mailman-2.1.12/Mailman/versions.py	2009-08-05 14:26:59.000000000 +0200
@@ -414,6 +414,9 @@
                         mm_cfg.DEFAULT_REGULAR_EXCLUDE_LISTS)
     add_only_if_missing('regular_include_lists',
                         mm_cfg.DEFAULT_REGULAR_INCLUDE_LISTS)
+    # discards email with no command
+    add_only_if_missing('discard_email_without_command',
+                        mm_cfg.DEFAULT_DISCARD_EMAIL_WITHOUT_COMMAND)