diff --git a/cores/arduino/IPAddress.cpp b/cores/arduino/IPAddress.cpp
new file mode 100644
index 0000000..0575363
--- /dev/null
+++ b/cores/arduino/IPAddress.cpp
@@ -0,0 +1,125 @@
+/*
+ IPAddress.cpp - Base class that provides IPAddress
+ Copyright (c) 2011 Adrian McEwen.  All right reserved.
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <Arduino.h>
+#include <IPAddress.h>
+#include <Print.h>
+
+IPAddress::IPAddress()
+{
+    _address.dword = 0;
+}
+
+IPAddress::IPAddress(uint8_t first_octet, uint8_t second_octet, uint8_t third_octet, uint8_t fourth_octet)
+{
+    _address.bytes[0] = first_octet;
+    _address.bytes[1] = second_octet;
+    _address.bytes[2] = third_octet;
+    _address.bytes[3] = fourth_octet;
+}
+
+IPAddress::IPAddress(uint32_t address)
+{
+    _address.dword = address;
+}
+
+IPAddress::IPAddress(const uint8_t *address)
+{
+    memcpy(_address.bytes, address, sizeof(_address.bytes));
+}
+
+IPAddress& IPAddress::operator=(const uint8_t *address)
+{
+    memcpy(_address.bytes, address, sizeof(_address.bytes));
+    return *this;
+}
+
+IPAddress& IPAddress::operator=(uint32_t address)
+{
+    _address.dword = address;
+    return *this;
+}
+
+bool IPAddress::operator==(const uint8_t* addr) const
+{
+    return memcmp(addr, _address.bytes, sizeof(_address.bytes)) == 0;
+}
+
+size_t IPAddress::printTo(Print& p) const
+{
+    size_t n = 0;
+    for(int i = 0; i < 3; i++) {
+        n += p.print(_address.bytes[i], DEC);
+        n += p.print('.');
+    }
+    n += p.print(_address.bytes[3], DEC);
+    return n;
+}
+
+String IPAddress::toString() const
+{
+    char szRet[16];
+    sprintf(szRet,"%u.%u.%u.%u", _address.bytes[0], _address.bytes[1], _address.bytes[2], _address.bytes[3]);
+    return String(szRet);
+}
+
+bool IPAddress::fromString(const char *address)
+{
+    // TODO: add support for "a", "a.b", "a.b.c" formats
+
+    uint16_t acc = 0; // Accumulator
+    uint8_t dots = 0;
+
+    while (*address)
+    {
+        char c = *address++;
+        if (c >= '0' && c <= '9')
+        {
+            acc = acc * 10 + (c - '0');
+            if (acc > 255) {
+                // Value out of [0..255] range
+                return false;
+            }
+        }
+        else if (c == '.')
+        {
+            if (dots == 3) {
+                // Too much dots (there must be 3 dots)
+                return false;
+            }
+            _address.bytes[dots++] = acc;
+            acc = 0;
+        }
+        else
+        {
+            // Invalid char
+            return false;
+        }
+    }
+
+    if (dots != 3) {
+        // Too few dots (there must be 3 dots)
+        return false;
+    }
+    _address.bytes[3] = acc;
+    return true;
+}
+
+// declared one time - as external in IPAddress.h
+IPAddress INADDR_NONE(0, 0, 0, 0);