diff --git a/CommandStation-EX.ino b/CommandStation-EX.ino
index 4872375..dbce4e7 100644
--- a/CommandStation-EX.ino
+++ b/CommandStation-EX.ino
@@ -69,7 +69,7 @@ void setup()
 //  Start the WiFi interface on a MEGA, Uno cannot currently handle WiFi
 
 #if WIFI_ON
-  WifiInterface::setup(WIFI_SERIAL_LINK_SPEED, F(WIFI_SSID), F(WIFI_PASSWORD), F(WIFI_HOSTNAME), IP_PORT);
+  WifiInterface::setup(WIFI_SERIAL_LINK_SPEED, F(WIFI_SSID), F(WIFI_PASSWORD), F(WIFI_HOSTNAME), 2560);
 #endif // WIFI_ON
 
 #if ETHERNET_ON
diff --git a/DCCTimer.cpp b/DCCTimer.cpp
index af10f8f..f1f3ba2 100644
--- a/DCCTimer.cpp
+++ b/DCCTimer.cpp
@@ -54,12 +54,16 @@ INTERRUPT_CALLBACK interruptHandler=0;
     TCB0.INTFLAGS = TCB_CAPT_bm;
     interruptHandler();
   }
-  
+
+  void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+    memcpy(mac,&SIGROW.SERNUM0,6);  // serial number
+  }
+
 #else 
-  // Arduino nano, uno, mega etc 
+  // Arduino nano, uno, mega etc
   void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
     interruptHandler=callback;
-    noInterrupts(); 
+    noInterrupts();          
     ADCSRA = (ADCSRA & 0b11111000) | 0b00000100;   // speed up analogRead sample time 
     TCCR1A = 0;
     ICR1 = CLOCK_CYCLES;
@@ -71,4 +75,10 @@ INTERRUPT_CALLBACK interruptHandler=0;
 
 // ISR called by timer interrupt every 58uS
   ISR(TIMER1_OVF_vect){ interruptHandler(); }
+
+  #include <avr/boot.h> 
+  void DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+    for (byte i=0; i<6; i++) mac[i]=boot_signature_byte_get(0x0E + i);
+  }
+
 #endif
diff --git a/DCCTimer.h b/DCCTimer.h
index a388349..1d17789 100644
--- a/DCCTimer.h
+++ b/DCCTimer.h
@@ -7,6 +7,7 @@ typedef void (*INTERRUPT_CALLBACK)();
 class DCCTimer {
   public:
   static void begin(INTERRUPT_CALLBACK interrupt);
+  static void getSimulatedMacAddress(byte mac[6]);
   private:
 };
 
diff --git a/EthernetInterface.cpp b/EthernetInterface.cpp
index 42d1bbb..2061aa6 100644
--- a/EthernetInterface.cpp
+++ b/EthernetInterface.cpp
@@ -17,12 +17,18 @@
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  * 
  */
-
+#if __has_include ( "config.h")
+  #include "config.h"
+#else
+  #warning config.h not found. Using defaults from config.example.h 
+  #include "config.example.h"
+#endif
 #include "defines.h" 
 #if ETHERNET_ON == true
 #include "EthernetInterface.h"
 #include "DIAG.h"
 #include "CommandDistributor.h"
+#include "DCCTimer.h"
 
 EthernetInterface * EthernetInterface::singleton=NULL;
 /**
@@ -44,10 +50,15 @@ void EthernetInterface::setup()
  */
 EthernetInterface::EthernetInterface()
 {
-    byte mac[]=MAC_ADDRESS;
+    byte mac[6];
+    DCCTimer::getSimulatedMacAddress(mac);
+    DIAG(F("\n+++++ Ethernet Setup. Simulatd mac="));
+    for (byte i=0;i<sizeof(mac); i++) {
+        DIAG(F("%x:"),mac[i]);
+    }
+    DIAG(F("\n"));
     
-    DIAG(F("\n+++++ Ethernet Setup "));
-        connected=false;
+    connected=false;
    
     #ifdef IP_ADDRESS
     Ethernet.begin(mac, IP_ADDRESS);
diff --git a/EthernetInterface.h b/EthernetInterface.h
index a7d4bb9..886fc52 100644
--- a/EthernetInterface.h
+++ b/EthernetInterface.h
@@ -38,11 +38,8 @@
  * @brief Network Configuration
  * 
  */
-#ifndef MAC_ADDRESS
-#error define MAC_ADDRESS in config.h
-#endif
 
-#define LISTEN_PORT 2560                                        // default listen port for the server 
+#define LISTEN_PORT 2560                      // standard listen port for the server 
 #define MAX_ETH_BUFFER 512
 #define OUTBOUND_RING_SIZE 2048
 
diff --git a/config.example.h b/config.example.h
index 2f5bf79..f5a67fc 100644
--- a/config.example.h
+++ b/config.example.h
@@ -26,12 +26,6 @@ The configuration file for DCC-EX Command Station
 //
 #define MOTOR_SHIELD_TYPE STANDARD_MOTOR_SHIELD
 
-/////////////////////////////////////////////////////////////////////////////////////
-//
-// The IP port to talk to a WIFI or Ethernet shield.
-//
-#define IP_PORT 2560
-
 /////////////////////////////////////////////////////////////////////////////////////
 //
 // NOTE: Only supported on Arduino Mega
@@ -89,26 +83,6 @@ The configuration file for DCC-EX Command Station
 //
 //#define IP_ADDRESS { 192, 168, 1, 200 }
 
-/////////////////////////////////////////////////////////////////////////////////////
-//
-// DEFINE MAC ADDRESS ARRAY FOR ETHERNET COMMUNICATIONS INTERFACE
-//
-// Uncomment to use with Ethernet Shields
-//
-// Ethernet Shields do not have have a MAC address in hardware. There may be one on 
-// a sticker on the Shield that you should use. Otherwise choose one of the ones below
-// Be certain that no other device on your network has this same MAC address!
-//
-// 52:b8:8a:8e:ce:21
-// e3:e9:73:e1:db:0d
-// 54:2b:13:52:ac:0c
-
-// NOTE: This is not used with ESP8266 WiFi modules.
-
-//#define MAC_ADDRESS { 0x52, 0xB8, 0x8A, 0x8E, 0xCE, 0x21 }      // MAC address of your networking card found on the sticker on your card or take one from above
-
-// 
-// #define MAC_ADDRESS {  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xEF }
 
 /////////////////////////////////////////////////////////////////////////////////////
 //