Ethernet

subnetMask()

Ethernet.subnetMask() returns the subnet mask of the network as an IPAddress.

SerialLogHandler logHandler;

void setup() {
 // Wait for a USB serial connection for up to 30 seconds
  waitFor(Serial.isConnected, 30000);

  // Prints out the subnet mask over Serial.
  Log.info(Ethernet.subnetMask());
}