Unable to get Arduino Ethernet Shield IP address connected to Raspberry

Question

My Arduino Uno with Ethernet Shield is connected to a Raspberry (rasp1) and the Ethernet Shield is connected to another Raspberry (rasp2) by Ethernet cable; rasp2 has a private IP address (192.168.10.0). I want to find out the Arduino IP address.

I used the example sketch DHCPAddressPrinter but when running it the Serial Monitor remains empty (as Mac Address I used the address located underneath the shield).

Code Used:

#include <SPI.h>
#include <Ethernet.h>
// Enter a MAC address for your controller below.
// Newer Ethernet shields have a MAC address printed on a sticker on the shield
byte mac[] = {
 0x90, 0xA2, 0xDA, 0x11, 0x32, 0x49
};
// Initialize the Ethernet client library
// with the IP address and port of the server
// that you want to connect to (port 80 is default for HTTP):
EthernetClient client;
void setup() {
 // Open serial communications and wait for port to open:
 Serial.begin(9600);
 // this check is only needed on the Leonardo:
 while (!Serial) {
 ; // wait for serial port to connect. Needed for Leonardo only
 }
 // start the Ethernet connection:
 if (Ethernet.begin(mac) == 0) {
 Serial.println("Failed to configure Ethernet using DHCP");
 // no point in carrying on, so do nothing forevermore:
 for (;;)
 ;
 }
 // print your local IP address:
 Serial.print("My IP address: ");
 for (byte thisByte = 0; thisByte < 4; thisByte++) {
 // print the value of each byte of the IP address:
 Serial.print(Ethernet.localIP()[thisByte], DEC);
 Serial.print(".");
 }
 Serial.println();
}
void loop() {

• jsotola: how are you connecting two ethernet cables to the ethernet shield?

Answer 1

192.168.10.0 is not a valid IP address (unless it's on a /32 subnet which makes no sense on ethernet).

You need to allocate a proper IP address within a proper subnet, such as 192.168.10.1/24 (i.e., IP 192.168.10.1 and netmask 255.255.255.0), and either manually provide a similar IP address to the Arduino (such as 192.168.10.2/24 [IP 192.168.10.2 netmask 255.255.255.0]), or install and configure a DHCP server on the Raspberry to hand out IP addresses within that subnet range (e.g., 192.168.10.100/24 to 192.168.10.200/24) for the Arduino to then be able to use DHCP mode.

Most of that is outside the scope of an Arduino SE site, though.