diff -r 345391bb8ee1 Lib/ipaddress.py
--- a/Lib/ipaddress.py	Sat Mar 01 02:04:10 2014 -0500
+++ b/Lib/ipaddress.py	Sun Mar 02 13:52:59 2014 +0100
@@ -691,7 +691,10 @@
             return False
         # dealing with another network.
         if isinstance(other, _BaseNetwork):
-            return False
+            return (
+                int(other.network_address) >= int(self.network_address) and
+                int(other.broadcast_address) <= int(self.broadcast_address)
+            )
         # dealing with another address
         else:
             # address
diff -r 345391bb8ee1 Lib/test/test_ipaddress.py
--- a/Lib/test/test_ipaddress.py	Sat Mar 01 02:04:10 2014 -0500
+++ b/Lib/test/test_ipaddress.py	Sun Mar 02 13:52:59 2014 +0100
@@ -530,6 +530,14 @@
     v6addr = ipaddress.IPv6Address(1)
     v6net = ipaddress.IPv6Network(1)
     v6intf = ipaddress.IPv6Interface(1)
+    v4smallnet_a = ipaddress.IPv4Network('10.0.0.0/30')
+    v4smallnet_b = ipaddress.IPv4Network('20.0.0.0/30')
+    v4smallnet_c = ipaddress.IPv4Network('30.0.0.0/30')
+    v4bignet = ipaddress.IPv4Network('20.0.0.0/24')
+    v6smallnet_a = ipaddress.IPv6Network('1000::/64')
+    v6smallnet_b = ipaddress.IPv6Network('2000::/64')
+    v6smallnet_c = ipaddress.IPv6Network('3000::/64')
+    v6bignet = ipaddress.IPv6Network('2000::/48')
 
     v4_addresses = [v4addr, v4intf]
     v4_objects = v4_addresses + [v4net]
@@ -560,10 +568,16 @@
             self.assertIn(obj, self.v4net)
         for obj in self.v6_addresses:
             self.assertIn(obj, self.v6net)
-        for obj in self.v4_objects + [self.v6net]:
+        for obj in self.v4_objects:
             self.assertNotIn(obj, self.v6net)
-        for obj in self.v6_objects + [self.v4net]:
+        for obj in self.v6_objects:
             self.assertNotIn(obj, self.v4net)
+        self.assertNotIn(self.v4smallnet_a, self.v4bignet)
+        self.assertIn(self.v4smallnet_b, self.v4bignet)
+        self.assertNotIn(self.v4smallnet_c, self.v4bignet)
+        self.assertNotIn(self.v6smallnet_a, self.v6bignet)
+        self.assertIn(self.v6smallnet_b, self.v6bignet)
+        self.assertNotIn(self.v6smallnet_c, self.v6bignet)
 
     def test_mixed_type_ordering(self):
         for lhs in self.objects: