diff --git a/cores/arduino/IPAddress.cpp b/cores/arduino/IPAddress.cpp
new file mode 100644
index 0000000..408d518
--- /dev/null
+++ b/cores/arduino/IPAddress.cpp
@@ -0,0 +1,44 @@
+
+#include <WProgram.h>
+#include <IPAddress.h>
+
+IPAddress::IPAddress()
+{
+    memset(_address, 0, sizeof(_address));
+}
+
+IPAddress::IPAddress(uint8_t first_octet, uint8_t second_octet, uint8_t third_octet, uint8_t fourth_octet)
+{
+    _address[0] = first_octet;
+    _address[1] = second_octet;
+    _address[2] = third_octet;
+    _address[3] = fourth_octet;
+}
+
+IPAddress::IPAddress(uint32_t address)
+{
+    memcpy(_address, &address, sizeof(_address));
+}
+
+IPAddress::IPAddress(const uint8_t *address)
+{
+    memcpy(_address, address, sizeof(_address));
+}
+
+IPAddress& IPAddress::operator=(const uint8_t *address)
+{
+    memcpy(_address, address, sizeof(_address));
+    return *this;
+}
+
+IPAddress& IPAddress::operator=(uint32_t address)
+{
+    memcpy(_address, (const uint8_t *)&address, sizeof(_address));
+    return *this;
+}
+
+bool IPAddress::operator==(const uint8_t* addr)
+{
+    return memcmp(addr, _address, sizeof(_address)) == 0;
+}
+
diff --git a/cores/arduino/IPAddress.h b/cores/arduino/IPAddress.h
new file mode 100644
index 0000000..487e420
--- /dev/null
+++ b/cores/arduino/IPAddress.h
@@ -0,0 +1,72 @@
+/*
+ *
+ * MIT License:
+ * Copyright (c) 2011 Adrian McEwen
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * adrianm@mcqn.com 1/1/2011
+ */
+
+#ifndef IPAddress_h
+#define IPAddress_h
+
+// A class to make it easier to handle and pass around IP addresses
+
+class IPAddress {
+private:
+    uint8_t _address[4];  // IPv4 address
+    // Access the raw byte array containing the address.  Because this returns a pointer
+    // to the internal structure rather than a copy of the address this function should only
+    // be used when you know that the usage of the returned uint8_t* will be transient and not
+    // stored.
+    uint8_t* raw_address() { return _address; };
+
+public:
+    // Constructors
+    IPAddress();
+    IPAddress(uint8_t first_octet, uint8_t second_octet, uint8_t third_octet, uint8_t fourth_octet);
+    IPAddress(uint32_t address);
+    IPAddress(const uint8_t *address);
+
+    // Overloaded cast operator to allow IPAddress objects to be used where a pointer
+    // to a four-byte uint8_t array is expected
+    operator uint32_t() { return *((uint32_t*)_address); };
+    bool operator==(const IPAddress& addr) { return (*((uint32_t*)_address)) == (*((uint32_t*)addr._address)); };
+    bool operator==(const uint8_t* addr);
+
+    // Overloaded index operator to allow getting and setting individual octets of the address
+    uint8_t operator[](int index) const { return _address[index]; };
+    uint8_t& operator[](int index) { return _address[index]; };
+
+    // Overloaded copy operators to allow initialisation of IPAddress objects from other types
+    IPAddress& operator=(const uint8_t *address);
+    IPAddress& operator=(uint32_t address);
+
+    friend class EthernetClass;
+    friend class UDP;
+    friend class Client;
+    friend class Server;
+    friend class DhcpClass;
+    friend class DNSClient;
+};
+
+const IPAddress INADDR_NONE(0,0,0,0);
+
+
+#endif
diff --git a/cores/arduino/NetClient.h b/cores/arduino/NetClient.h
new file mode 100644
index 0000000..d8df914
--- /dev/null
+++ b/cores/arduino/NetClient.h
@@ -0,0 +1,28 @@
+#ifndef netclient_h
+#define netclient_h
+#include "WProgram.h"	
+#include "Print.h"
+#include "NetClient.h"
+#include "IPAddress.h"
+
+class NetClient : public Stream {
+
+public:
+  virtual int connect(IPAddress ip, uint16_t port) =0;
+  virtual int connect(const char *host, uint16_t port) =0;
+  virtual void write(uint8_t) =0;
+  virtual void write(const char *str) =0;
+  virtual void write(const uint8_t *buf, size_t size) =0;
+  virtual int available() = 0;
+  virtual int read() = 0;
+  virtual int read(uint8_t *buf, size_t size) = 0;
+  virtual int peek() = 0;
+  virtual void flush() = 0;
+  virtual void stop() = 0;
+  virtual uint8_t connected() = 0;
+  virtual uint8_t operator==(int) = 0;
+  virtual uint8_t operator!=(int) = 0;
+  virtual operator bool() = 0;
+};
+
+#endif