--- a/Lib/ftplib.py
+++ b/Lib/ftplib.py
@@ -343,19 +343,23 @@
             host, port = self.makepasv()
             conn = socket.create_connection((host, port), self.timeout,
                                             source_address=self.source_address)
-            if rest is not None:
-                self.sendcmd("REST %s" % rest)
-            resp = self.sendcmd(cmd)
-            # Some servers apparently send a 200 reply to
-            # a LIST or STOR command, before the 150 reply
-            # (and way before the 226 reply). This seems to
-            # be in violation of the protocol (which only allows
-            # 1xx or error messages for LIST), so we just discard
-            # this response.
-            if resp[0] == '2':
-                resp = self.getresp()
-            if resp[0] != '1':
-                raise error_reply(resp)
+            try:
+                if rest is not None:
+                    self.sendcmd("REST %s" % rest)
+                resp = self.sendcmd(cmd)
+                # Some servers apparently send a 200 reply to
+                # a LIST or STOR command, before the 150 reply
+                # (and way before the 226 reply). This seems to
+                # be in violation of the protocol (which only allows
+                # 1xx or error messages for LIST), so we just discard
+                # this response.
+                if resp[0] == '2':
+                    resp = self.getresp()
+                if resp[0] != '1':
+                    raise error_reply(resp)
+            except:
+                conn.close()
+                raise
         else:
             sock = self.makeport()
             if rest is not None: