diff --git a/PubSubClient/PubSubClient.cpp b/PubSubClient/PubSubClient.cpp
index c4da0c5..cb9ca68 100755
--- a/PubSubClient/PubSubClient.cpp
+++ b/PubSubClient/PubSubClient.cpp
@@ -5,7 +5,6 @@
 */
 
 #include "PubSubClient.h"
-#include <string.h>
 
 PubSubClient::PubSubClient() {
    this->_client = NULL;
@@ -13,31 +12,73 @@ PubSubClient::PubSubClient() {
    setCallback(NULL);
 }
 
-PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, void (*callback)(char*,uint8_t*,unsigned int), Client& client) {
+PubSubClient::PubSubClient(IPAddress addr, uint16_t port, Client& client) {
+   setServer(addr, port);
    setClient(client);
-   setCallback(callback);
-   setServer(ip, port);
    this->stream = NULL;
 }
-
-PubSubClient::PubSubClient(char* domain, uint16_t port, void (*callback)(char*,uint8_t*,unsigned int), Client& client) {
+PubSubClient::PubSubClient(IPAddress addr, uint16_t port, Client& client, Stream& stream) {
+   setServer(addr,port);
    setClient(client);
+   setStream(stream);
+}
+PubSubClient::PubSubClient(IPAddress addr, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client& client) {
+   setServer(addr, port);
    setCallback(callback);
-   setServer(domain,port);
+   setClient(client);
    this->stream = NULL;
 }
-
-PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, void (*callback)(char*,uint8_t*,unsigned int), Client& client, Stream& stream) {
-   setClient(client);
+PubSubClient::PubSubClient(IPAddress addr, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client& client, Stream& stream) {
+   setServer(addr,port);
    setCallback(callback);
-   setServer(ip,port);
+   setClient(client);
    setStream(stream);
 }
 
-PubSubClient::PubSubClient(char* domain, uint16_t port, void (*callback)(char*,uint8_t*,unsigned int), Client& client, Stream& stream) {
+
+PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, Client& client) {
+   setServer(ip, port);
    setClient(client);
+   this->stream = NULL;
+}
+PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, Client& client, Stream& stream) {
+   setServer(ip,port);
+   setClient(client);
+   setStream(stream);
+}
+PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client& client) {
+   setServer(ip, port);
    setCallback(callback);
+   setClient(client);
+   this->stream = NULL;
+}
+PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client& client, Stream& stream) {
+   setServer(ip,port);
+   setCallback(callback);
+   setClient(client);
+   setStream(stream);
+}
+
+PubSubClient::PubSubClient(char* domain, uint16_t port, Client& client) {
    setServer(domain,port);
+   setClient(client);
+   this->stream = NULL;
+}
+PubSubClient::PubSubClient(char* domain, uint16_t port, Client& client, Stream& stream) {
+   setServer(domain,port);
+   setClient(client);
+   setStream(stream);
+}
+PubSubClient::PubSubClient(char* domain, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client& client) {
+   setServer(domain,port);
+   setCallback(callback);
+   setClient(client);
+   this->stream = NULL;
+}
+PubSubClient::PubSubClient(char* domain, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client& client, Stream& stream) {
+   setServer(domain,port);
+   setCallback(callback);
+   setClient(client);
    setStream(stream);
 }
 
@@ -49,8 +90,7 @@ boolean PubSubClient::connect(char *id, char *user, char *pass) {
    return connect(id,user,pass,0,0,0,0);
 }
 
-boolean PubSubClient::connect(char *id, char* willTopic, uint8_t willQos, uint8_t willRetain, char* willMessage)
-{
+boolean PubSubClient::connect(char *id, char* willTopic, uint8_t willQos, uint8_t willRetain, char* willMessage) {
    return connect(id,NULL,NULL,willTopic,willQos,willRetain,willMessage);
 }
 
@@ -63,7 +103,6 @@ boolean PubSubClient::connect(char *id, char *user, char *pass, char* willTopic,
       } else {
         result = _client->connect(this->ip, this->port);
       }
-
       if (result) {
          nextMsgId = 1;
          // Leave room in the buffer for header and variable length field
@@ -429,6 +468,11 @@ boolean PubSubClient::connected() {
 }
 
 void PubSubClient::setServer(uint8_t * ip, uint16_t port) {
+    IPAddress addr(ip[0],ip[1],ip[2],ip[3]);
+    setServer(addr,port);
+}
+
+void PubSubClient::setServer(IPAddress ip, uint16_t port) {
     this->ip = ip;
     this->port = port;
 }
diff --git a/PubSubClient/PubSubClient.h b/PubSubClient/PubSubClient.h
index 3e5dbdd..f472774 100755
--- a/PubSubClient/PubSubClient.h
+++ b/PubSubClient/PubSubClient.h
@@ -8,6 +8,7 @@
 #define PubSubClient_h
 
 #include <Arduino.h>
+#include "IPAddress.h"
 #include "Client.h"
 #include "Stream.h"
 
@@ -43,6 +44,8 @@
 #define MQTTQOS1        (1 << 1)
 #define MQTTQOS2        (2 << 1)
 
+#define MQTT_CALLBACK_SIGNATURE void (*callback)(char*,uint8_t*,unsigned int)
+
 class PubSubClient {
 private:
    Client* _client;
@@ -51,25 +54,34 @@ private:
    unsigned long lastOutActivity;
    unsigned long lastInActivity;
    bool pingOutstanding;
-   void (*callback)(char*,uint8_t*,unsigned int);
+   MQTT_CALLBACK_SIGNATURE;
    uint16_t readPacket(uint8_t*);
    uint8_t readByte();
    boolean write(uint8_t header, uint8_t* buf, uint16_t length);
    uint16_t writeString(char* string, uint8_t* buf, uint16_t pos);
-   uint8_t *ip;
+   IPAddress ip;
    char* domain;
    uint16_t port;
    Stream* stream;
 public:
    PubSubClient();
-   PubSubClient(uint8_t *, uint16_t, void(*)(char*,uint8_t*,unsigned int),Client& client);
-   PubSubClient(uint8_t *, uint16_t, void(*)(char*,uint8_t*,unsigned int),Client& client, Stream&);
-   PubSubClient(char*, uint16_t, void(*)(char*,uint8_t*,unsigned int),Client& client);
-   PubSubClient(char*, uint16_t, void(*)(char*,uint8_t*,unsigned int),Client& client, Stream&);
+   PubSubClient(IPAddress, uint16_t, Client& client);
+   PubSubClient(IPAddress, uint16_t, Client& client, Stream&);
+   PubSubClient(IPAddress, uint16_t, MQTT_CALLBACK_SIGNATURE,Client& client);
+   PubSubClient(IPAddress, uint16_t, MQTT_CALLBACK_SIGNATURE,Client& client, Stream&);
+   PubSubClient(uint8_t *, uint16_t, Client& client);
+   PubSubClient(uint8_t *, uint16_t, Client& client, Stream&);
+   PubSubClient(uint8_t *, uint16_t, MQTT_CALLBACK_SIGNATURE,Client& client);
+   PubSubClient(uint8_t *, uint16_t, MQTT_CALLBACK_SIGNATURE,Client& client, Stream&);
+   PubSubClient(char*, uint16_t, Client& client);
+   PubSubClient(char*, uint16_t, Client& client, Stream&);
+   PubSubClient(char*, uint16_t, MQTT_CALLBACK_SIGNATURE,Client& client);
+   PubSubClient(char*, uint16_t, MQTT_CALLBACK_SIGNATURE,Client& client, Stream&);
 
+   void setServer(IPAddress ip, uint16_t port);
    void setServer(uint8_t * ip, uint16_t port);
    void setServer(char * domain, uint16_t port);
-   void setCallback(void(*callback)(char*,uint8_t*,unsigned int));
+   void setCallback(MQTT_CALLBACK_SIGNATURE);
    void setClient(Client& client);
    void setStream(Stream& stream);
 
diff --git a/PubSubClient/examples/mqtt_auth/mqtt_auth.ino b/PubSubClient/examples/mqtt_auth/mqtt_auth.ino
index c8a519a..f4c38f3 100755
--- a/PubSubClient/examples/mqtt_auth/mqtt_auth.ino
+++ b/PubSubClient/examples/mqtt_auth/mqtt_auth.ino
@@ -1,6 +1,6 @@
 /*
  Basic MQTT example with Authentication
- 
+
   - connects to an MQTT server, providing username
     and password
   - publishes "hello world" to the topic "outTopic"
@@ -13,8 +13,8 @@
 
 // Update these with values suitable for your network.
 byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
-byte server[] = { 172, 16, 0, 2 };
-byte ip[]     = { 172, 16, 0, 100 };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
 
 void callback(char* topic, byte* payload, unsigned int length) {
   // handle message arrived
@@ -36,4 +36,3 @@ void loop()
 {
   client.loop();
 }
-
diff --git a/PubSubClient/examples/mqtt_basic/mqtt_basic.ino b/PubSubClient/examples/mqtt_basic/mqtt_basic.ino
index 72276cd..88e77de 100755
--- a/PubSubClient/examples/mqtt_basic/mqtt_basic.ino
+++ b/PubSubClient/examples/mqtt_basic/mqtt_basic.ino
@@ -1,6 +1,6 @@
 /*
- Basic MQTT example 
- 
+ Basic MQTT example
+
   - connects to an MQTT server
   - publishes "hello world" to the topic "outTopic"
   - subscribes to the topic "inTopic"
@@ -12,8 +12,8 @@
 
 // Update these with values suitable for your network.
 byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
-byte server[] = { 172, 16, 0, 2 };
-byte ip[]     = { 172, 16, 0, 100 };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
 
 void callback(char* topic, byte* payload, unsigned int length) {
   // handle message arrived
@@ -35,4 +35,3 @@ void loop()
 {
   client.loop();
 }
-
diff --git a/PubSubClient/examples/mqtt_publish_in_callback/mqtt_publish_in_callback.ino b/PubSubClient/examples/mqtt_publish_in_callback/mqtt_publish_in_callback.ino
index ece5c2e..42afb2a 100644
--- a/PubSubClient/examples/mqtt_publish_in_callback/mqtt_publish_in_callback.ino
+++ b/PubSubClient/examples/mqtt_publish_in_callback/mqtt_publish_in_callback.ino
@@ -1,17 +1,17 @@
 /*
- Publishing in the callback 
- 
+ Publishing in the callback
+
   - connects to an MQTT server
   - subscribes to the topic "inTopic"
   - when a message is received, republishes it to "outTopic"
-  
+
   This example shows how to publish messages within the
   callback function. The callback function header needs to
-  be declared before the PubSubClient constructor and the 
+  be declared before the PubSubClient constructor and the
   actual callback defined afterwards.
   This ensures the client reference in the callback function
   is valid.
-  
+
 */
 
 #include <SPI.h>
@@ -20,8 +20,8 @@
 
 // Update these with values suitable for your network.
 byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
-byte server[] = { 172, 16, 0, 2 };
-byte ip[]     = { 172, 16, 0, 100 };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
 
 // Callback function header
 void callback(char* topic, byte* payload, unsigned int length);
@@ -34,7 +34,7 @@ void callback(char* topic, byte* payload, unsigned int length) {
   // In order to republish this payload, a copy must be made
   // as the orignal payload buffer will be overwritten whilst
   // constructing the PUBLISH packet.
-  
+
   // Allocate the correct amount of memory for the payload copy
   byte* p = (byte*)malloc(length);
   // Copy the payload to the new buffer
@@ -46,7 +46,7 @@ void callback(char* topic, byte* payload, unsigned int length) {
 
 void setup()
 {
-  
+
   Ethernet.begin(mac, ip);
   if (client.connect("arduinoClient")) {
     client.publish("outTopic","hello world");
@@ -58,4 +58,3 @@ void loop()
 {
   client.loop();
 }
-
diff --git a/PubSubClient/examples/mqtt_stream/mqtt_stream.ino b/PubSubClient/examples/mqtt_stream/mqtt_stream.ino
index a416ee2..67c2287 100644
--- a/PubSubClient/examples/mqtt_stream/mqtt_stream.ino
+++ b/PubSubClient/examples/mqtt_stream/mqtt_stream.ino
@@ -16,8 +16,8 @@
 
 // Update these with values suitable for your network.
 byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
-byte server[] = { 172, 16, 0, 2 };
-byte ip[]     = { 172, 16, 0, 100 };
+IPAddress ip(172, 16, 0, 100);
+IPAddress server(172, 16, 0, 2);
 
 SRAM sram(4, SRAM_1024);
 
@@ -29,7 +29,7 @@ void callback(char* topic, byte* payload, unsigned int length) {
     Serial.write(sram.read());
   }
   Serial.println();
-  
+
   // Reset position for the next message to be stored
   sram.seek(1);
 }
@@ -47,7 +47,7 @@ void setup()
 
   sram.begin();
   sram.seek(1);
-  
+
   Serial.begin(9600);
 }
 
@@ -55,4 +55,3 @@ void loop()
 {
   client.loop();
 }
-