DHCP Faild!

I have an arduino uno and ethernet shield. I did all the instruction needed to work and start my project but it can’t to connect to the interrnet , when viewing serial monitor it dispalys DHCP Faild!.

Welcome to Cayenne!

Can you post your sketch for us too?

try a reset on the ethernet chip at the start of your setup…i had similar issues

Hey there.
I have the same problem. I have tryed with manual and auto connection, but the follow message is displayed:
0] Getting IP…
[60445] DHCP Failed!
[0] MAC: FE-A3-DC-D7-E4-D8
[1] Getting IP…
[60446] DHCP Failed!
[1] MAC: FE-A3-DC-D7-E4-D8
[1] Getting IP…
[60447] DHCP Failed!

The courios is that with the network of my office the shield works fine, but the same arduino with the same sketch doesn´t work in the network of my house (same IP config, same hardware…). I have tryed resseting the arduino, changing the IP address, opening ports in the modem…
for your reference I send you the sketch used:

//#define CAYENNE_DEBUG // Uncomment to show debug messages
#define CAYENNE_PRINT Serial // Comment this out to disable prints and save space
#include <CayenneEthernet.h>

// Cayenne authentication token. This should be obtained from the Cayenne Dashboard.
char token[] = “”;

void setup()
_ Serial.begin(9600);_
_ Cayenne.begin(token);_

void loop()
_ Cayenne.run();_



I got the same issue, the solutions is to solder two 100 ohm resistor

Maybe obscure the token in your code

Can you plug in another device to the same cable that goes to the arduino? Like a laptop, etc. This will tell us if it’s a hardware problem.

Hello. I have done that checking too. If I connect the shield directly to my laptop, the device makes ping. But when I reconnect the shield to the router the shield doesn’t work. It is not hardware problem.

Believe me i had the exact same problem if i used the connection from my laptop i could get ip and same problem connect back to my router try the resistance and you will see

Where did you find that fix? Seems like a crazy solution!

I dunno about you,
-but I’ve been humbled soooo many times
as a computer field engineer @ DataPoint
…I just SMH and accept…
hey, if it works…

One more thing that just came to mind is crossover cables. Assuming they followed the client networking standard you shouldn’t need a crossover cable, but anything is possible. Almost all laptop now come with gigabit networking which autodetect and correct for crossovers, but gigabit on home routers is only common in the last 3 years or so. Might be worth trying?

I found it on arduino forum the problem is about the poor quality of chinese shield…

Over here full explanation : Ethernet sheild(W5100) not working with Uno - Networking, Protocols, and Devices - Arduino Forum

1 Like

Nice find @flammeur.
Enough people responded to that link
that I (personally) would call it resolved.
Poor Chineese manufacturing,
wrong resistor network matching.
They SHOULD have used 50 ohms,
instead they used 500 ohms.

friend, its not clear in the picture which pin is connected with resistance , can you specify the pin numbers here ?

thanks in advance.

Very ugly but you should get it

thanks much …