diff --git a/src/calibre/srv/loop.py b/src/calibre/srv/loop.py
index 2d489b7c5a..1a60c1adc3 100644
--- a/src/calibre/srv/loop.py
+++ b/src/calibre/srv/loop.py
@@ -28,6 +28,7 @@ from calibre.utils.mdns import get_external_ip
 
 READ, WRITE, RDWR, WAIT = 'READ', 'WRITE', 'RDWR', 'WAIT'
 WAKEUP, JOB_DONE = bytes(bytearray(xrange(2)))
+IPPROTO_IPV6 = getattr(socket, "IPPROTO_IPV6", 41)
 
 
 class ReadBuffer(object):  # {{{
@@ -485,8 +486,7 @@ class ServerLoop(object):
         if (hasattr(socket, 'AF_INET6') and self.socket.family == socket.AF_INET6 and
                 self.bind_address[0] in ('::', '::0', '::0.0.0.0')):
             try:
-                self.socket.setsockopt(
-                    socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 0)
+                self.socket.setsockopt(IPPROTO_IPV6, socket.IPV6_V6ONLY, 0)
             except (AttributeError, socket.error):
                 # Apparently, the socket option is not available in
                 # this machine's TCP stack
diff --git a/src/calibre/srv/tests/loop.py b/src/calibre/srv/tests/loop.py
index a3b1dbb962..695f8f85b7 100644
--- a/src/calibre/srv/tests/loop.py
+++ b/src/calibre/srv/tests/loop.py
@@ -127,15 +127,18 @@ class LoopTest(BaseTest):
         self.assertTrue(b.stopped.wait(5), 'BonJour not stopped')
 
     def test_dual_stack(self):
+        from calibre.srv.loop import IPPROTO_IPV6
         with TestServer(lambda data:(data.path[0] + data.read()), listen_on='::') as server:
             self.ae(server.address[0], '::')
-            self.ae(server.loop.socket.getsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY), 0)
+            self.ae(server.loop.socket.getsockopt(IPPROTO_IPV6, socket.IPV6_V6ONLY), 0)
             for interface in ('::1', '127.0.0.1'):
                 conn = server.connect(interface=interface)
                 conn.request('GET', '/test', 'body')
                 r = conn.getresponse()
                 self.ae(r.status, httplib.OK)
                 self.ae(r.read(), b'testbody')
+                r.close()
+                conn.close()
 
     def test_ring_buffer(self):
         'Test the ring buffer used for reads'