diff --git a/Lib/smtplib.py b/Lib/smtplib.py
index d37b0e2..44a144c 100644
--- a/Lib/smtplib.py
+++ b/Lib/smtplib.py
@@ -309,7 +309,7 @@
                 try:
                     port = int(port)
                 except ValueError:
-                    raise socket.error("nonnumeric port")
+                    raise OSError("nonnumeric port")
         if not port:
             port = self.default_port
         if self.debuglevel > 0:
@@ -330,7 +330,7 @@
                 s = s.encode("ascii")
             try:
                 self.sock.sendall(s)
-            except socket.error:
+            except OSError:
                 self.close()
                 raise SMTPServerDisconnected('Server not connected')
         else:
@@ -363,7 +363,7 @@
         while 1:
             try:
                 line = self.file.readline()
-            except socket.error as e:
+            except OSError as e:
                 self.close()
                 raise SMTPServerDisconnected("Connection unexpectedly closed: "
                                              + str(e))
@@ -920,13 +920,13 @@
             self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
             self.file = None
             self.sock.connect(host)
-        except socket.error as msg:
+        except OSError:
             if self.debuglevel > 0:
                 print('connect fail:', host, file=stderr)
             if self.sock:
                 self.sock.close()
             self.sock = None
-            raise socket.error(msg)
+            raise
         (code, msg) = self.getreply()
         if self.debuglevel > 0:
             print('connect:', msg, file=stderr)
diff --git a/Lib/test/mock_socket.py b/Lib/test/mock_socket.py
index d09e78c..8ef0ec8 100644
--- a/Lib/test/mock_socket.py
+++ b/Lib/test/mock_socket.py
@@ -140,12 +140,8 @@
     return ""
 
 
-class gaierror(Exception):
-    pass
-
-
-class error(Exception):
-    pass
+gaierror = socket_module.gaierror
+error = socket_module.error
 
 
 # Constants
diff --git a/Lib/test/test_smtplib.py b/Lib/test/test_smtplib.py
index befc49e..6fe2df9 100644
--- a/Lib/test/test_smtplib.py
+++ b/Lib/test/test_smtplib.py
@@ -542,9 +542,9 @@
 
     def testNonnumericPort(self):
         # check that non-numeric port raises socket.error
-        self.assertRaises(mock_socket.error, smtplib.SMTP,
+        self.assertRaises(OSError, smtplib.SMTP,
                           "localhost", "bogus")
-        self.assertRaises(mock_socket.error, smtplib.SMTP,
+        self.assertRaises(OSError, smtplib.SMTP,
                           "localhost:bogus")