Index: Lib/ftplib.py
===================================================================
--- Lib/ftplib.py	(revisione 84233)
+++ Lib/ftplib.py	(copia locale)
@@ -571,7 +571,11 @@
 
     def mkd(self, dirname):
         '''Make a directory, return its full pathname.'''
-        resp = self.sendcmd('MKD ' + dirname)
+        resp = self.voidcmd('MKD ' + dirname)
+        # fix around non-compliant implementations such as IIS shipped
+        # with Windows server 2003
+        if not resp.startswith('257'):
+            return ''
         return parse257(resp)
 
     def rmd(self, dirname):
@@ -580,7 +584,11 @@
 
     def pwd(self):
         '''Return current working directory.'''
-        resp = self.sendcmd('PWD')
+        resp = self.voidcmd('PWD')
+        # fix around non-compliant implementations such as IIS shipped
+        # with Windows server 2003
+        if not resp.startswith('257'):
+            return ''
         return parse257(resp)
 
     def quit(self):
Index: Lib/test/test_ftplib.py
===================================================================
--- Lib/test/test_ftplib.py	(revisione 84233)
+++ Lib/test/test_ftplib.py	(copia locale)
@@ -606,7 +606,19 @@
         self.assertEqual(self.server.handler_instance.last_received_cmd, 'quit')
         self.assertFalse(is_client_connected())
 
+    def test_parse257(self):
+        self.assertEqual(ftplib.parse257('257 "/foo/bar"'), '/foo/bar')
+        self.assertEqual(ftplib.parse257('257 "/foo/bar" created'), '/foo/bar')
+        self.assertEqual(ftplib.parse257('257 ""'), '')
+        self.assertEqual(ftplib.parse257('257 "" created'), '')
+        self.assertRaises(ftplib.error_reply, ftplib.parse257, '250 "/foo/bar"')
+        # The 257 response is supposed to include the directory
+        # name and in case it contains embedded double-quotes
+        # they must be doubled (see RFC-959, chapter 7, appendix 2).
+        self.assertEqual(ftplib.parse257('257 "/foo/b""ar"'), '/foo/b"ar')
+        self.assertEqual(ftplib.parse257('257 "/foo/b""ar" created'), '/foo/b"ar')
 
+
 class TestIPv6Environment(TestCase):
 
     def setUp(self):