diff -r 3ae2cd85a908 Doc/library/smtpd.rst
--- a/Doc/library/smtpd.rst	Sun Mar 09 11:18:16 2014 +0100
+++ b/Doc/library/smtpd.rst	Mon Jun 09 15:50:04 2014 +0200
@@ -59,6 +59,9 @@
    .. versionchanged:: 3.4
       The *map* argument was added.
 
+   .. versionchanged:: 3.5
+      IPv6 support was added.
+
 
 DebuggingServer Objects
 -----------------------
diff -r 3ae2cd85a908 Lib/smtpd.py
--- a/Lib/smtpd.py	Sun Mar 09 11:18:16 2014 +0100
+++ b/Lib/smtpd.py	Mon Jun 09 15:50:04 2014 +0200
@@ -583,7 +583,8 @@
         self.data_size_limit = data_size_limit
         asyncore.dispatcher.__init__(self, map=map)
         try:
-            self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
+            gai_results = socket.getaddrinfo(localaddr[0], localaddr[1])
+            self.create_socket(gai_results[0][0], gai_results[0][1])
             # try to re-use a server port if possible
             self.set_reuse_addr()
             self.bind(localaddr)
diff -r 3ae2cd85a908 Lib/test/mock_socket.py
--- a/Lib/test/mock_socket.py	Sun Mar 09 11:18:16 2014 +0100
+++ b/Lib/test/mock_socket.py	Mon Jun 09 15:50:04 2014 +0200
@@ -35,8 +35,9 @@
 class MockSocket:
     """Mock socket object used by smtpd and smtplib tests.
     """
-    def __init__(self):
+    def __init__(self, family=None):
         global _reply_data
+        self.family = family
         self.output = []
         self.lines = []
         if _reply_data:
@@ -108,8 +109,7 @@
 
 
 def socket(family=None, type=None, proto=None):
-    return MockSocket()
-
+    return MockSocket(family)
 
 def create_connection(address, timeout=socket_module._GLOBAL_DEFAULT_TIMEOUT,
                       source_address=None):
@@ -144,13 +144,16 @@
 def gethostbyname(name):
     return ""
 
+def getaddrinfo(host, port):
+    return socket_module.getaddrinfo(host, port)
 
 gaierror = socket_module.gaierror
 error = socket_module.error
 
 
 # Constants
-AF_INET = None
+AF_INET = socket_module.AF_INET
+AF_INET6 = socket_module.AF_INET6
 SOCK_STREAM = None
 SOL_SOCKET = None
 SO_REUSEADDR = None
diff -r 3ae2cd85a908 Lib/test/test_smtpd.py
--- a/Lib/test/test_smtpd.py	Sun Mar 09 11:18:16 2014 +0100
+++ b/Lib/test/test_smtpd.py	Mon Jun 09 15:50:04 2014 +0200
@@ -27,11 +27,21 @@
 
 
 class SMTPDServerTest(unittest.TestCase):
+    def write_line(self, line):
+        self.channel.socket.queue_recv(line)
+        self.channel.handle_read()
+
+    def empty_message(self):
+        self.write_line(b'HELO example')
+        self.write_line(b'MAIL From:eggs@example')
+        self.write_line(b'RCPT To:spam@example')
+        self.write_line(b'DATA')
+
     def setUp(self):
         smtpd.socket = asyncore.socket = mock_socket
 
     def test_process_message_unimplemented(self):
-        server = smtpd.SMTPServer('a', 'b')
+        server = smtpd.SMTPServer(support.HOST, 'b')
         conn, addr = server.accept()
         channel = smtpd.SMTPChannel(server, conn, addr)
 
@@ -49,13 +59,22 @@
         asyncore.close_all()
         asyncore.socket = smtpd.socket = socket
 
+class TestFamilyDetection(unittest.TestCase):
+    @unittest.skipUnless(support.IPV6_ENABLED, "IPv6 not enabled")
+    def test_socket_uses_IPv6(self):
+        server = smtpd.SMTPServer((support.HOSTv6, 0), (support.HOST, 0))
+        self.assertEqual(server.socket.family, socket.AF_INET6)
+
+    def test_socket_uses_IPv4(self):
+        server = smtpd.SMTPServer((support.HOST, 0), (support.HOSTv6, 0))
+        self.assertEqual(server.socket.family, socket.AF_INET)
 
 class SMTPDChannelTest(unittest.TestCase):
     def setUp(self):
         smtpd.socket = asyncore.socket = mock_socket
         self.old_debugstream = smtpd.DEBUGSTREAM
         self.debug = smtpd.DEBUGSTREAM = io.StringIO()
-        self.server = DummyServer('a', 'b')
+        self.server = DummyServer((support.HOST, 0), ('b', 0))
         conn, addr = self.server.accept()
         self.channel = smtpd.SMTPChannel(self.server, conn, addr)
 
@@ -69,7 +88,8 @@
         self.channel.handle_read()
 
     def test_broken_connect(self):
-        self.assertRaises(DummyDispatcherBroken, BrokenDummyServer, 'a', 'b')
+        self.assertRaises(
+            DummyDispatcherBroken, BrokenDummyServer, support.HOST, 'b')
 
     def test_server_accept(self):
         self.server.handle_accept()
@@ -502,6 +522,15 @@
         with support.check_warnings(('', DeprecationWarning)):
             self.channel._SMTPChannel__addr = 'spam'
 
+@unittest.skipUnless(support.IPV6_ENABLED, "IPv6 not enabled")
+class SMTPDChannelIPv6Test(SMTPDChannelTest):
+    def setUp(self):
+        smtpd.socket = asyncore.socket = mock_socket
+        self.old_debugstream = smtpd.DEBUGSTREAM
+        self.debug = smtpd.DEBUGSTREAM = io.StringIO()
+        self.server = DummyServer((support.HOSTv6, 0), ('b', 0))
+        conn, addr = self.server.accept()
+        self.channel = smtpd.SMTPChannel(self.server, conn, addr)
 
 class SMTPDChannelWithDataSizeLimitTest(unittest.TestCase):
 
@@ -509,7 +538,7 @@
         smtpd.socket = asyncore.socket = mock_socket
         self.old_debugstream = smtpd.DEBUGSTREAM
         self.debug = smtpd.DEBUGSTREAM = io.StringIO()
-        self.server = DummyServer('a', 'b')
+        self.server = DummyServer((support.HOST, 0), ('b', 0))
         conn, addr = self.server.accept()
         # Set DATA size limit to 32 bytes for easy testing
         self.channel = smtpd.SMTPChannel(self.server, conn, addr, 32)