--- smtplib.py	2008-05-29 09:39:26.000000000 -0700
+++ smtplibx.py	2009-10-22 10:44:01.750000000 -0700
@@ -694,7 +694,10 @@
 
         (code,resp) = self.mail(from_addr, esmtp_opts)
         if code != 250:
-            self.rset()
+            if code == 421:
+                self.close()
+            else:
+                self.rset()
             raise SMTPSenderRefused(code, resp, from_addr)
         senderrs={}
         if isinstance(to_addrs, basestring):
@@ -703,13 +706,19 @@
             (code,resp)=self.rcpt(each, rcpt_options)
             if (code != 250) and (code != 251):
                 senderrs[each]=(code,resp)
+            if code == 421:
+                self.close()
+                raise SMTPRecipientsRefused(senderrs)
         if len(senderrs)==len(to_addrs):
             # the server refused all our recipients
             self.rset()
             raise SMTPRecipientsRefused(senderrs)
         (code,resp) = self.data(msg)
         if code != 250:
-            self.rset()
+            if code == 421:
+                self.close()
+            else:
+                self.rset()
             raise SMTPDataError(code, resp)
         #if we got here then somebody got our mail
         return senderrs