diff --git a/protocol/artistic/artnet/device.cpp b/protocol/artistic/artnet/device.cpp
index 20853b6..6a548a2 100644
--- a/protocol/artistic/artnet/device.cpp
+++ b/protocol/artistic/artnet/device.cpp
@@ -511,6 +511,19 @@ ipAddress Device::broadcastIp() const
 }
 
 
+/**
+ * @brief Device::deviceSubnetMask
+ * @return
+ *
+ * The default implimenation is to return an invalid mask.
+ * \note Platform aware device types must return their valid subnet mask.
+ */
+uint32_t Device::deviceSubnetMask() const
+{
+    return -1;
+}
+
+
 /**
  * @brief Device::deviceHasDHCP
  * @return
diff --git a/protocol/artistic/artnet/device.h b/protocol/artistic/artnet/device.h
index febeb31..8302047 100644
--- a/protocol/artistic/artnet/device.h
+++ b/protocol/artistic/artnet/device.h
@@ -92,6 +92,7 @@ protected:
   // OSI layer 3
   virtual ipAddress deviceIp() const;
   virtual ipAddress broadcastIp() const;
+  virtual uint32_t deviceSubnetMask() const;
   virtual bool deviceHasDHCP() const;
 
 private: