diff --git a/ip.cpp.rl b/ip.cpp.rl
index d1ccac3e..5a028159 100644
--- a/ip.cpp.rl
+++ b/ip.cpp.rl
@@ -14,7 +14,7 @@
  * You should have received a copy of the GNU General Public License
  * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
  *
- * Copyright 2011 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2011-2016 Danny Robson <danny@nerdcruft.net>
  */
 
 
@@ -35,9 +35,9 @@ const ipv4::ip ipv4::ip::ANY      (  0, 0, 0, 0);
 
 
 //-----------------------------------------------------------------------------
-const util::range<ipv4::port> ipv4::WELL_KNOWN_PORT (    0,  1023),
-                              ipv4::REGISTERED_PORT ( 1024, 49151),
-                              ipv4::PRIVATE_PORT    (49152, 65535);
+const util::range<ipv4::port_t> ipv4::WELL_KNOWN_PORT (    0,  1023),
+                                ipv4::REGISTERED_PORT ( 1024, 49151),
+                                ipv4::PRIVATE_PORT    (49152, 65535);
 
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -131,7 +131,7 @@ ipv4::ip::ip (const std::string &data)
     %%write exec;
 
     if (!__success)
-        throw invalid_argument(data);
+        throw ipv4::error ();
 
     m_octets[0] = __octets[0];
     m_octets[1] = __octets[1];
diff --git a/ip.hpp b/ip.hpp
index e7a1ab72..61318eea 100644
--- a/ip.hpp
+++ b/ip.hpp
@@ -11,7 +11,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
- * Copyright 2011 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2011-2016 Danny Robson <danny@nerdcruft.net>
  */
 
 #ifndef __UTIL_IP_HPP
@@ -46,12 +46,15 @@ namespace ipv4 {
     };
 
 
-    typedef uint16_t port;
-    typedef uint32_t mask;
+    typedef uint16_t port_t;
+    typedef uint32_t mask_t;
+
+    extern const util::range<port_t> WELL_KNOWN_PORT,
+                                     REGISTERED_PORT,
+                                     PRIVATE_PORT;
+
+    class error : public std::exception { };
 
-    extern const util::range<port> WELL_KNOWN_PORT,
-                             REGISTERED_PORT,
-                             PRIVATE_PORT;
 }
 
 
@@ -62,13 +65,15 @@ namespace ipv6 {
         explicit ip (const std::string&) { ; }
     };
 
-    typedef uint16_t port;
+    typedef uint16_t port_t;
 
-    struct mask {
+    struct mask_t {
         uint32_t m_quads[4];
 
-        explicit mask (uint32_t) { ; }
+        explicit mask_t (uint32_t) { ; }
     };
+
+    class error : public std::exception { };
 }
 
 
diff --git a/net/address.hpp b/net/address.hpp
index 10e307d6..538ac185 100644
--- a/net/address.hpp
+++ b/net/address.hpp
@@ -37,18 +37,18 @@ namespace net {
 
     template <>
     struct address_types <domain::INET> {
-        typedef ipv4::ip    ip;
-        typedef ipv4::mask  mask;
-        typedef ipv4::port  port;
-        typedef sockaddr_in sockaddr;
+        typedef ipv4::ip     ip;
+        typedef ipv4::mask_t mask_t;
+        typedef ipv4::port_t port_t;
+        typedef sockaddr_in  sockaddr;
     };
 
 
     template <>
     struct address_types <domain::INET6> {
         typedef ipv6::ip     ip;
-        typedef ipv6::mask   mask;
-        typedef ipv6::port   port;
+        typedef ipv6::mask_t mask_t;
+        typedef ipv6::port_t port_t;
         typedef sockaddr_in6 sockaddr;
     };
 
@@ -58,8 +58,8 @@ namespace net {
     class address {
         public:
             typedef typename address_types<D>::ip       ip_type;
-            typedef typename address_types<D>::mask     mask_type;
-            typedef typename address_types<D>::port     port_type;
+            typedef typename address_types<D>::mask_t   mask_type;
+            typedef typename address_types<D>::port_t   port_type;
             typedef typename address_types<D>::sockaddr sockaddr_type;
 
         protected: