diff --git a/trunk/ipaddr.py b/trunk/ipaddr.py
index <HASH>..<HASH> 100644
--- a/trunk/ipaddr.py
+++ b/trunk/ipaddr.py
@@ -1045,6 +1045,17 @@ class _BaseV4(object):
         return self in IPv4Network('224.0.0.0/4')
 
     @property
+    def is_unspecified(self):
+        """Test if the address is unspecified.
+
+        Returns:
+            A boolean, True if this is the unspecified address as defined in
+            RFC 5735 3.
+
+        """
+        return self in IPv4Network('0.0.0.0')
+
+    @property
     def is_loopback(self):
         """Test if the address is a loopback address.
 
diff --git a/trunk/ipaddr_test.py b/trunk/ipaddr_test.py
index <HASH>..<HASH> 100755
--- a/trunk/ipaddr_test.py
+++ b/trunk/ipaddr_test.py
@@ -656,6 +656,8 @@ class IpaddrUnitTest(unittest.TestCase):
         self.assertEquals(True, ipaddr.IPAddress('127.42.0.0').is_loopback)
         self.assertEquals(False, ipaddr.IPAddress('128.0.0.0').is_loopback)
 
+        self.assertEquals(True, ipaddr.IPNetwork('0.0.0.0').is_unspecified)
+
         
     def testReservedIpv6(self):
+ add IPv4Network().is_unspecified. issue<I>.

 (thanks to rep.dot.net for the bug report and patch).

git-svn-id: <URL>