--- D:/apps/Python26/Lib/email/utils-trunk.py	Tue Aug 04 00:20:31 2009
+++ D:/apps/Python26/Lib/email/utils.py	Tue Aug 04 00:05:43 2009
@@ -172,6 +172,19 @@
 
 
 
+try:
+    from threading import Lock
+except ImportError:
+    from dummy_threading import Lock
+_next_number_lock = Lock()
+
+def _gen_next_number():
+    while True:
+        for number in xrange(100000):
+            yield number
+
+_next_number = _gen_next_number().next
+
 def make_msgid(idstring=None):
     """Returns a string suitable for RFC 2822 compliant Message-ID, e.g:
 
@@ -183,13 +196,14 @@
     timeval = time.time()
     utcdate = time.strftime('%Y%m%d%H%M%S', time.gmtime(timeval))
     pid = os.getpid()
-    randint = random.randrange(100000)
+    with _next_number_lock:
+        seqint = _next_number()
     if idstring is None:
         idstring = ''
     else:
         idstring = '.' + idstring
     idhost = socket.getfqdn()
-    msgid = '<%s.%s.%s%s@%s>' % (utcdate, pid, randint, idstring, idhost)
+    msgid = '<%s.%s.%s%s@%s>' % (utcdate, pid, seqint, idstring, idhost)
     return msgid